Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * verify_nbtree.c
4 : : * Verifies the integrity of nbtree indexes based on invariants.
5 : : *
6 : : * For B-Tree indexes, verification includes checking that each page in the
7 : : * target index has items in logical order as reported by an insertion scankey
8 : : * (the insertion scankey sort-wise NULL semantics are needed for
9 : : * verification).
10 : : *
11 : : * When index-to-heap verification is requested, a Bloom filter is used to
12 : : * fingerprint all tuples in the target index, as the index is traversed to
13 : : * verify its structure. A heap scan later uses Bloom filter probes to verify
14 : : * that every visible heap tuple has a matching index tuple.
15 : : *
16 : : *
17 : : * Copyright (c) 2017-2026, PostgreSQL Global Development Group
18 : : *
19 : : * IDENTIFICATION
20 : : * contrib/amcheck/verify_nbtree.c
21 : : *
22 : : *-------------------------------------------------------------------------
23 : : */
24 : : #include "postgres.h"
25 : :
26 : : #include "access/heaptoast.h"
27 : : #include "access/htup_details.h"
28 : : #include "access/nbtree.h"
29 : : #include "access/table.h"
30 : : #include "access/tableam.h"
31 : : #include "access/transam.h"
32 : : #include "access/xact.h"
33 : : #include "verify_common.h"
34 : : #include "catalog/index.h"
35 : : #include "catalog/pg_am.h"
36 : : #include "catalog/pg_opfamily_d.h"
37 : : #include "common/pg_prng.h"
38 : : #include "lib/bloomfilter.h"
39 : : #include "miscadmin.h"
40 : : #include "storage/smgr.h"
41 : : #include "utils/guc.h"
42 : : #include "utils/memutils.h"
43 : : #include "utils/snapmgr.h"
44 : :
45 : :
354 tgl@sss.pgh.pa.us 46 :CBC 329 : PG_MODULE_MAGIC_EXT(
47 : : .name = "amcheck",
48 : : .version = PG_VERSION
49 : : );
50 : :
51 : : /*
52 : : * A B-Tree cannot possibly have this many levels, since there must be one
53 : : * block per level, which is bound by the range of BlockNumber:
54 : : */
55 : : #define InvalidBtreeLevel ((uint32) InvalidBlockNumber)
56 : : #define BTreeTupleGetNKeyAtts(itup, rel) \
57 : : Min(IndexRelationGetNumberOfKeyAttributes(rel), BTreeTupleGetNAtts(itup, rel))
58 : :
59 : : /*
60 : : * State associated with verifying a B-Tree index
61 : : *
62 : : * target is the point of reference for a verification operation.
63 : : *
64 : : * Other B-Tree pages may be allocated, but those are always auxiliary (e.g.,
65 : : * they are current target's child pages). Conceptually, problems are only
66 : : * ever found in the current target page (or for a particular heap tuple during
67 : : * heapallindexed verification). Each page found by verification's left/right,
68 : : * top/bottom scan becomes the target exactly once.
69 : : */
70 : : typedef struct BtreeCheckState
71 : : {
72 : : /*
73 : : * Unchanging state, established at start of verification:
74 : : */
75 : :
76 : : /* B-Tree Index Relation and associated heap relation */
77 : : Relation rel;
78 : : Relation heaprel;
79 : : /* rel is heapkeyspace index? */
80 : : bool heapkeyspace;
81 : : /* ShareLock held on heap/index, rather than AccessShareLock? */
82 : : bool readonly;
83 : : /* Also verifying heap has no unindexed tuples? */
84 : : bool heapallindexed;
85 : : /* Also making sure non-pivot tuples can be found by new search? */
86 : : bool rootdescend;
87 : : /* Also check uniqueness constraint if index is unique */
88 : : bool checkunique;
89 : : /* Per-page context */
90 : : MemoryContext targetcontext;
91 : : /* Buffer access strategy */
92 : : BufferAccessStrategy checkstrategy;
93 : :
94 : : /*
95 : : * Info for uniqueness checking. Fill this field and the one below once
96 : : * per index check.
97 : : */
98 : : IndexInfo *indexinfo;
99 : : /* Table scan snapshot for heapallindexed and checkunique */
100 : : Snapshot snapshot;
101 : :
102 : : /*
103 : : * Mutable state, for verification of particular page:
104 : : */
105 : :
106 : : /* Current target page */
107 : : Page target;
108 : : /* Target block number */
109 : : BlockNumber targetblock;
110 : : /* Target page's LSN */
111 : : XLogRecPtr targetlsn;
112 : :
113 : : /*
114 : : * Low key: high key of left sibling of target page. Used only for child
115 : : * verification. So, 'lowkey' is kept only when 'readonly' is set.
116 : : */
117 : : IndexTuple lowkey;
118 : :
119 : : /*
120 : : * The rightlink and incomplete split flag of block one level down to the
121 : : * target page, which was visited last time via downlink from target page.
122 : : * We use it to check for missing downlinks.
123 : : */
124 : : BlockNumber prevrightlink;
125 : : bool previncompletesplit;
126 : :
127 : : /*
128 : : * Mutable state, for optional heapallindexed verification:
129 : : */
130 : :
131 : : /* Bloom filter fingerprints B-Tree index */
132 : : bloom_filter *filter;
133 : : /* Debug counter */
134 : : int64 heaptuplespresent;
135 : : } BtreeCheckState;
136 : :
137 : : /*
138 : : * Starting point for verifying an entire B-Tree index level
139 : : */
140 : : typedef struct BtreeLevel
141 : : {
142 : : /* Level number (0 is leaf page level). */
143 : : uint32 level;
144 : :
145 : : /* Left most block on level. Scan of level begins here. */
146 : : BlockNumber leftmost;
147 : :
148 : : /* Is this level reported as "true" root level by meta page? */
149 : : bool istruerootlevel;
150 : : } BtreeLevel;
151 : :
152 : : /*
153 : : * Information about the last visible entry with current B-tree key. Used
154 : : * for validation of the unique constraint.
155 : : */
156 : : typedef struct BtreeLastVisibleEntry
157 : : {
158 : : BlockNumber blkno; /* Index block */
159 : : OffsetNumber offset; /* Offset on index block */
160 : : int postingIndex; /* Number in the posting list (-1 for
161 : : * non-deduplicated tuples) */
162 : : ItemPointer tid; /* Heap tid */
163 : : } BtreeLastVisibleEntry;
164 : :
165 : : /*
166 : : * arguments for the bt_index_check_callback callback
167 : : */
168 : : typedef struct BTCallbackState
169 : : {
170 : : bool parentcheck;
171 : : bool heapallindexed;
172 : : bool rootdescend;
173 : : bool checkunique;
174 : : } BTCallbackState;
175 : :
3293 andres@anarazel.de 176 : 97 : PG_FUNCTION_INFO_V1(bt_index_check);
177 : 75 : PG_FUNCTION_INFO_V1(bt_index_parent_check);
178 : :
179 : : static void bt_index_check_callback(Relation indrel, Relation heaprel,
180 : : void *state, bool readonly);
181 : : static void bt_check_every_level(Relation rel, Relation heaprel,
182 : : bool heapkeyspace, bool readonly, bool heapallindexed,
183 : : bool rootdescend, bool checkunique);
184 : : static BtreeLevel bt_check_level_from_leftmost(BtreeCheckState *state,
185 : : BtreeLevel level);
186 : : static bool bt_leftmost_ignoring_half_dead(BtreeCheckState *state,
187 : : BlockNumber start,
188 : : BTPageOpaque start_opaque);
189 : : static void bt_recheck_sibling_links(BtreeCheckState *state,
190 : : BlockNumber btpo_prev_from_target,
191 : : BlockNumber leftcurrent);
192 : : static bool heap_entry_is_visible(BtreeCheckState *state, ItemPointer tid);
193 : : static void bt_report_duplicate(BtreeCheckState *state,
194 : : BtreeLastVisibleEntry *lVis,
195 : : ItemPointer nexttid,
196 : : BlockNumber nblock, OffsetNumber noffset,
197 : : int nposting);
198 : : static void bt_entry_unique_check(BtreeCheckState *state, IndexTuple itup,
199 : : BlockNumber targetblock, OffsetNumber offset,
200 : : BtreeLastVisibleEntry *lVis);
201 : : static void bt_target_page_check(BtreeCheckState *state);
202 : : static BTScanInsert bt_right_page_check_scankey(BtreeCheckState *state,
203 : : OffsetNumber *rightfirstoffset);
204 : : static void bt_child_check(BtreeCheckState *state, BTScanInsert targetkey,
205 : : OffsetNumber downlinkoffnum);
206 : : static void bt_child_highkey_check(BtreeCheckState *state,
207 : : OffsetNumber target_downlinkoffnum,
208 : : Page loaded_child,
209 : : uint32 target_level);
210 : : static void bt_downlink_missing_check(BtreeCheckState *state, bool rightsplit,
211 : : BlockNumber blkno, Page page);
212 : : static void bt_tuple_present_callback(Relation index, ItemPointer tid,
213 : : Datum *values, bool *isnull,
214 : : bool tupleIsAlive, void *checkstate);
215 : : static IndexTuple bt_normalize_tuple(BtreeCheckState *state,
216 : : IndexTuple itup);
217 : : static inline IndexTuple bt_posting_plain_tuple(IndexTuple itup, int n);
218 : : static bool bt_rootdescend(BtreeCheckState *state, IndexTuple itup);
219 : : static inline bool offset_is_negative_infinity(BTPageOpaque opaque,
220 : : OffsetNumber offset);
221 : : static inline bool invariant_l_offset(BtreeCheckState *state, BTScanInsert key,
222 : : OffsetNumber upperbound);
223 : : static inline bool invariant_leq_offset(BtreeCheckState *state,
224 : : BTScanInsert key,
225 : : OffsetNumber upperbound);
226 : : static inline bool invariant_g_offset(BtreeCheckState *state, BTScanInsert key,
227 : : OffsetNumber lowerbound);
228 : : static inline bool invariant_l_nontarget_offset(BtreeCheckState *state,
229 : : BTScanInsert key,
230 : : BlockNumber nontargetblock,
231 : : Page nontarget,
232 : : OffsetNumber upperbound);
233 : : static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum);
234 : : static inline BTScanInsert bt_mkscankey_pivotsearch(Relation rel,
235 : : IndexTuple itup);
236 : : static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block,
237 : : Page page, OffsetNumber offset);
238 : : static inline ItemPointer BTreeTupleGetHeapTIDCareful(BtreeCheckState *state,
239 : : IndexTuple itup, bool nonpivot);
240 : : static inline ItemPointer BTreeTupleGetPointsToTID(IndexTuple itup);
241 : :
242 : : /*
243 : : * bt_index_check(index regclass, heapallindexed boolean, checkunique boolean)
244 : : *
245 : : * Verify integrity of B-Tree index.
246 : : *
247 : : * Acquires AccessShareLock on heap & index relations. Does not consider
248 : : * invariants that exist between parent/child pages. Optionally verifies
249 : : * that heap does not contain any unindexed or incorrectly indexed tuples.
250 : : */
251 : : Datum
252 : 3938 : bt_index_check(PG_FUNCTION_ARGS)
253 : : {
254 : 3938 : Oid indrelid = PG_GETARG_OID(0);
255 : : BTCallbackState args;
256 : :
351 tomas.vondra@postgre 257 : 3938 : args.heapallindexed = false;
258 : 3938 : args.rootdescend = false;
259 : 3938 : args.parentcheck = false;
260 : 3938 : args.checkunique = false;
261 : :
869 akorotkov@postgresql 262 [ + + ]: 3938 : if (PG_NARGS() >= 2)
351 tomas.vondra@postgre 263 : 3932 : args.heapallindexed = PG_GETARG_BOOL(1);
264 [ + + ]: 3938 : if (PG_NARGS() >= 3)
265 : 682 : args.checkunique = PG_GETARG_BOOL(2);
266 : :
267 : 3938 : amcheck_lock_relation_and_check(indrelid, BTREE_AM_OID,
268 : : bt_index_check_callback,
269 : : AccessShareLock, &args);
270 : :
3293 andres@anarazel.de 271 : 3912 : PG_RETURN_VOID();
272 : : }
273 : :
274 : : /*
275 : : * bt_index_parent_check(index regclass, heapallindexed boolean, rootdescend boolean, checkunique boolean)
276 : : *
277 : : * Verify integrity of B-Tree index.
278 : : *
279 : : * Acquires ShareLock on heap & index relations. Verifies that downlinks in
280 : : * parent pages are valid lower bounds on child pages. Optionally verifies
281 : : * that heap does not contain any unindexed or incorrectly indexed tuples.
282 : : */
283 : : Datum
284 : 69 : bt_index_parent_check(PG_FUNCTION_ARGS)
285 : : {
286 : 69 : Oid indrelid = PG_GETARG_OID(0);
287 : : BTCallbackState args;
288 : :
351 tomas.vondra@postgre 289 : 69 : args.heapallindexed = false;
290 : 69 : args.rootdescend = false;
291 : 69 : args.parentcheck = true;
292 : 69 : args.checkunique = false;
293 : :
2552 pg@bowt.ie 294 [ + + ]: 69 : if (PG_NARGS() >= 2)
351 tomas.vondra@postgre 295 : 63 : args.heapallindexed = PG_GETARG_BOOL(1);
869 akorotkov@postgresql 296 [ + + ]: 69 : if (PG_NARGS() >= 3)
351 tomas.vondra@postgre 297 : 59 : args.rootdescend = PG_GETARG_BOOL(2);
298 [ + + ]: 69 : if (PG_NARGS() >= 4)
299 : 26 : args.checkunique = PG_GETARG_BOOL(3);
300 : :
301 : 69 : amcheck_lock_relation_and_check(indrelid, BTREE_AM_OID,
302 : : bt_index_check_callback,
303 : : ShareLock, &args);
304 : :
3293 andres@anarazel.de 305 : 51 : PG_RETURN_VOID();
306 : : }
307 : :
308 : : /*
309 : : * Helper for bt_index_[parent_]check, coordinating the bulk of the work.
310 : : */
311 : : static void
351 tomas.vondra@postgre 312 : 4001 : bt_index_check_callback(Relation indrel, Relation heaprel, void *state, bool readonly)
313 : : {
314 : 4001 : BTCallbackState *args = (BTCallbackState *) state;
315 : : bool heapkeyspace,
316 : : allequalimage;
317 : :
318 [ + + ]: 4001 : if (!smgrexists(RelationGetSmgr(indrel), MAIN_FORKNUM))
3293 andres@anarazel.de 319 [ + - ]: 18 : ereport(ERROR,
320 : : (errcode(ERRCODE_INDEX_CORRUPTED),
321 : : errmsg("index \"%s\" lacks a main relation fork",
322 : : RelationGetRelationName(indrel))));
323 : :
324 : : /* Extract metadata from metapage, and sanitize it in passing */
351 tomas.vondra@postgre 325 : 3983 : _bt_metaversion(indrel, &heapkeyspace, &allequalimage);
326 [ + + - + ]: 3983 : if (allequalimage && !heapkeyspace)
351 tomas.vondra@postgre 327 [ # # ]:UBC 0 : ereport(ERROR,
328 : : (errcode(ERRCODE_INDEX_CORRUPTED),
329 : : errmsg("index \"%s\" metapage has equalimage field set on unsupported nbtree version",
330 : : RelationGetRelationName(indrel))));
351 tomas.vondra@postgre 331 [ + + - + ]:CBC 3983 : if (allequalimage && !_bt_allequalimage(indrel, false))
332 : : {
351 tomas.vondra@postgre 333 :UBC 0 : bool has_interval_ops = false;
334 : :
335 [ # # ]: 0 : for (int i = 0; i < IndexRelationGetNumberOfKeyAttributes(indrel); i++)
336 [ # # ]: 0 : if (indrel->rd_opfamily[i] == INTERVAL_BTREE_FAM_OID)
337 : : {
338 : 0 : has_interval_ops = true;
339 [ # # # # ]: 0 : ereport(ERROR,
340 : : (errcode(ERRCODE_INDEX_CORRUPTED),
341 : : errmsg("index \"%s\" metapage incorrectly indicates that deduplication is safe",
342 : : RelationGetRelationName(indrel)),
343 : : has_interval_ops
344 : : ? errhint("This is known of \"interval\" indexes last built on a version predating 2023-11.")
345 : : : 0));
346 : : }
347 : : }
348 : :
349 : : /* Check index, possibly against table it is an index on */
351 tomas.vondra@postgre 350 :CBC 3983 : bt_check_every_level(indrel, heaprel, heapkeyspace, readonly,
351 : 3983 : args->heapallindexed, args->rootdescend, args->checkunique);
2407 pg@bowt.ie 352 : 3963 : }
353 : :
354 : : /*
355 : : * Main entry point for B-Tree SQL-callable functions. Walks the B-Tree in
356 : : * logical order, verifying invariants as it goes. Optionally, verification
357 : : * checks if the heap relation contains any tuples that are not represented in
358 : : * the index but should be.
359 : : *
360 : : * It is the caller's responsibility to acquire appropriate heavyweight lock on
361 : : * the index relation, and advise us if extra checks are safe when a ShareLock
362 : : * is held. (A lock of the same type must also have been acquired on the heap
363 : : * relation.)
364 : : *
365 : : * A ShareLock is generally assumed to prevent any kind of physical
366 : : * modification to the index structure, including modifications that VACUUM may
367 : : * make. This does not include setting of the LP_DEAD bit by concurrent index
368 : : * scans, although that is just metadata that is not able to directly affect
369 : : * any check performed here. Any concurrent process that might act on the
370 : : * LP_DEAD bit being set (recycle space) requires a heavyweight lock that
371 : : * cannot be held while we hold a ShareLock. (Besides, even if that could
372 : : * happen, the ad-hoc recycling when a page might otherwise split is performed
373 : : * per-page, and requires an exclusive buffer lock, which wouldn't cause us
374 : : * trouble. _bt_delitems_vacuum() may only delete leaf items, and so the extra
375 : : * parent/child check cannot be affected.)
376 : : */
377 : : static void
2552 378 : 3983 : bt_check_every_level(Relation rel, Relation heaprel, bool heapkeyspace,
379 : : bool readonly, bool heapallindexed, bool rootdescend,
380 : : bool checkunique)
381 : : {
382 : : BtreeCheckState *state;
383 : : Page metapage;
384 : : BTMetaPageData *metad;
385 : : uint32 previouslevel;
386 : : BtreeLevel current;
387 : :
2165 388 [ + + ]: 3983 : if (!readonly)
389 [ + + ]: 3926 : elog(DEBUG1, "verifying consistency of tree structure for index \"%s\"",
390 : : RelationGetRelationName(rel));
391 : : else
392 [ + + ]: 57 : elog(DEBUG1, "verifying consistency of tree structure for index \"%s\" with cross-level checks",
393 : : RelationGetRelationName(rel));
394 : :
395 : : /*
396 : : * This assertion matches the one in index_getnext_tid(). See page
397 : : * recycling/"visible to everyone" notes in nbtree README.
398 : : */
2041 andres@anarazel.de 399 [ - + ]: 3983 : Assert(TransactionIdIsValid(RecentXmin));
400 : :
401 : : /*
402 : : * Initialize state for entire verification operation
403 : : */
100 michael@paquier.xyz 404 :GNC 3983 : state = palloc0_object(BtreeCheckState);
3293 andres@anarazel.de 405 :CBC 3983 : state->rel = rel;
2906 406 : 3983 : state->heaprel = heaprel;
2552 pg@bowt.ie 407 : 3983 : state->heapkeyspace = heapkeyspace;
3293 andres@anarazel.de 408 : 3983 : state->readonly = readonly;
2906 409 : 3983 : state->heapallindexed = heapallindexed;
2552 pg@bowt.ie 410 : 3983 : state->rootdescend = rootdescend;
869 akorotkov@postgresql 411 : 3983 : state->checkunique = checkunique;
412 : 3983 : state->snapshot = InvalidSnapshot;
413 : :
2906 andres@anarazel.de 414 [ + + ]: 3983 : if (state->heapallindexed)
415 : : {
416 : : int64 total_pages;
417 : : int64 total_elems;
418 : : uint64 seed;
419 : :
420 : : /*
421 : : * Size Bloom filter based on estimated number of tuples in index,
422 : : * while conservatively assuming that each block must contain at least
423 : : * MaxTIDsPerBTreePage / 3 "plain" tuples -- see
424 : : * bt_posting_plain_tuple() for definition, and details of how posting
425 : : * list tuples are handled.
426 : : */
2430 pg@bowt.ie 427 : 82 : total_pages = RelationGetNumberOfBlocks(rel);
2209 428 : 82 : total_elems = Max(total_pages * (MaxTIDsPerBTreePage / 3),
429 : : (int64) state->rel->rd_rel->reltuples);
430 : : /* Generate a random seed to avoid repetition */
1568 tgl@sss.pgh.pa.us 431 : 82 : seed = pg_prng_uint64(&pg_global_prng_state);
432 : : /* Create Bloom filter to fingerprint index */
2906 andres@anarazel.de 433 : 82 : state->filter = bloom_create(total_elems, maintenance_work_mem, seed);
434 : 82 : state->heaptuplespresent = 0;
435 : :
436 : : /*
437 : : * Register our own snapshot for heapallindexed, rather than asking
438 : : * table_index_build_scan() to do this for us later. This needs to
439 : : * happen before index fingerprinting begins, so we can later be
440 : : * certain that index fingerprinting should have reached all tuples
441 : : * returned by table_index_build_scan().
442 : : */
101 alvherre@kurilemu.de 443 : 82 : state->snapshot = RegisterSnapshot(GetTransactionSnapshot());
444 : :
445 : : /*
446 : : * GetTransactionSnapshot() always acquires a new MVCC snapshot in
447 : : * READ COMMITTED mode. A new snapshot is guaranteed to have all the
448 : : * entries it requires in the index.
449 : : *
450 : : * We must defend against the possibility that an old xact snapshot
451 : : * was returned at higher isolation levels when that snapshot is not
452 : : * safe for index scans of the target index. This is possible when
453 : : * the snapshot sees tuples that are before the index's indcheckxmin
454 : : * horizon. Throwing an error here should be very rare. It doesn't
455 : : * seem worth using a secondary snapshot to avoid this.
456 : : */
457 [ - + - - ]: 82 : if (IsolationUsesXactSnapshot() && rel->rd_index->indcheckxmin &&
101 alvherre@kurilemu.de 458 [ # # ]:UBC 0 : !TransactionIdPrecedes(HeapTupleHeaderGetXmin(rel->rd_indextuple->t_data),
459 : 0 : state->snapshot->xmin))
460 [ # # ]: 0 : ereport(ERROR,
461 : : errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
462 : : errmsg("index \"%s\" cannot be verified using transaction snapshot",
463 : : RelationGetRelationName(rel)));
464 : : }
465 : :
466 : : /*
467 : : * We need a snapshot to check the uniqueness of the index. For better
468 : : * performance, take it once per index check. If one was already taken
469 : : * above, use that.
470 : : */
869 akorotkov@postgresql 471 [ + + ]:CBC 3983 : if (state->checkunique)
472 : : {
473 : 704 : state->indexinfo = BuildIndexInfo(state->rel);
474 : :
101 alvherre@kurilemu.de 475 [ + + + + ]: 704 : if (state->indexinfo->ii_Unique && state->snapshot == InvalidSnapshot)
476 : 621 : state->snapshot = RegisterSnapshot(GetTransactionSnapshot());
477 : : }
478 : :
2552 pg@bowt.ie 479 [ + + - + ]: 3983 : Assert(!state->rootdescend || state->readonly);
480 [ + + - + ]: 3983 : if (state->rootdescend && !state->heapkeyspace)
2552 pg@bowt.ie 481 [ # # ]:UBC 0 : ereport(ERROR,
482 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
483 : : errmsg("cannot verify that tuples from index \"%s\" can each be found by an independent index search",
484 : : RelationGetRelationName(rel)),
485 : : errhint("Only B-Tree version 4 indexes support rootdescend verification.")));
486 : :
487 : : /* Create context for page */
3293 andres@anarazel.de 488 :CBC 3983 : state->targetcontext = AllocSetContextCreate(CurrentMemoryContext,
489 : : "amcheck context",
490 : : ALLOCSET_DEFAULT_SIZES);
491 : 3983 : state->checkstrategy = GetAccessStrategy(BAS_BULKREAD);
492 : :
493 : : /* Get true root block from meta-page */
494 : 3983 : metapage = palloc_btree_page(state, BTREE_METAPAGE);
495 : 3983 : metad = BTPageGetMeta(metapage);
496 : :
497 : : /*
498 : : * Certain deletion patterns can result in "skinny" B-Tree indexes, where
499 : : * the fast root and true root differ.
500 : : *
501 : : * Start from the true root, not the fast root, unlike conventional index
502 : : * scans. This approach is more thorough, and removes the risk of
503 : : * following a stale fast root from the meta page.
504 : : */
505 [ + + ]: 3983 : if (metad->btm_fastroot != metad->btm_root)
506 [ - + ]: 13 : ereport(DEBUG1,
507 : : (errcode(ERRCODE_NO_DATA),
508 : : errmsg_internal("harmless fast root mismatch in index \"%s\"",
509 : : RelationGetRelationName(rel)),
510 : : errdetail_internal("Fast root block %u (level %u) differs from true root block %u (level %u).",
511 : : metad->btm_fastroot, metad->btm_fastlevel,
512 : : metad->btm_root, metad->btm_level)));
513 : :
514 : : /*
515 : : * Starting at the root, verify every level. Move left to right, top to
516 : : * bottom. Note that there may be no pages other than the meta page (meta
517 : : * page can indicate that root is P_NONE when the index is totally empty).
518 : : */
519 : 3983 : previouslevel = InvalidBtreeLevel;
520 : 3983 : current.level = metad->btm_level;
521 : 3983 : current.leftmost = metad->btm_root;
522 : 3983 : current.istruerootlevel = true;
523 [ + + ]: 6493 : while (current.leftmost != P_NONE)
524 : : {
525 : : /*
526 : : * Verify this level, and get left most page for next level down, if
527 : : * not at leaf level
528 : : */
529 : 2528 : current = bt_check_level_from_leftmost(state, current);
530 : :
531 [ - + ]: 2510 : if (current.leftmost == InvalidBlockNumber)
3293 andres@anarazel.de 532 [ # # ]:UBC 0 : ereport(ERROR,
533 : : (errcode(ERRCODE_INDEX_CORRUPTED),
534 : : errmsg("index \"%s\" has no valid pages on level below %u or first level",
535 : : RelationGetRelationName(rel), previouslevel)));
536 : :
3293 andres@anarazel.de 537 :CBC 2510 : previouslevel = current.level;
538 : : }
539 : :
540 : : /*
541 : : * * Check whether heap contains unindexed/malformed tuples *
542 : : */
2906 543 [ + + ]: 3965 : if (state->heapallindexed)
544 : : {
545 : 75 : IndexInfo *indexinfo = BuildIndexInfo(state->rel);
546 : : TableScanDesc scan;
547 : :
548 : : /*
549 : : * Create our own scan for table_index_build_scan(), rather than
550 : : * getting it to do so for us. This is required so that we can
551 : : * actually use the MVCC snapshot registered earlier.
552 : : *
553 : : * Note that table_index_build_scan() calls heap_endscan() for us.
554 : : */
2545 555 : 75 : scan = table_beginscan_strat(state->heaprel, /* relation */
556 : : state->snapshot, /* snapshot */
557 : : 0, /* number of keys */
558 : : NULL, /* scan key */
559 : : true, /* buffer access strategy OK */
560 : : true); /* syncscan OK? */
561 : :
562 : : /*
563 : : * Scan will behave as the first scan of a CREATE INDEX CONCURRENTLY
564 : : * behaves.
565 : : *
566 : : * It's okay that we don't actually use the same lock strength for the
567 : : * heap relation as any other ii_Concurrent caller would. We have no
568 : : * reason to care about a concurrent VACUUM operation, since there
569 : : * isn't going to be a second scan of the heap that needs to be sure
570 : : * that there was no concurrent recycling of TIDs.
571 : : */
101 alvherre@kurilemu.de 572 : 73 : indexinfo->ii_Concurrent = true;
573 : :
574 : : /*
575 : : * Don't wait for uncommitted tuple xact commit/abort when index is a
576 : : * unique index on a catalog (or an index used by an exclusion
577 : : * constraint). This could otherwise happen in the readonly case.
578 : : */
2906 andres@anarazel.de 579 : 73 : indexinfo->ii_Unique = false;
580 : 73 : indexinfo->ii_ExclusionOps = NULL;
581 : 73 : indexinfo->ii_ExclusionProcs = NULL;
582 : 73 : indexinfo->ii_ExclusionStrats = NULL;
583 : :
584 [ + + ]: 73 : elog(DEBUG1, "verifying that tuples from index \"%s\" are present in \"%s\"",
585 : : RelationGetRelationName(state->rel),
586 : : RelationGetRelationName(state->heaprel));
587 : :
2539 alvherre@alvh.no-ip. 588 : 73 : table_index_build_scan(state->heaprel, state->rel, indexinfo, true, false,
589 : : bt_tuple_present_callback, state, scan);
590 : :
2906 andres@anarazel.de 591 [ + + ]: 73 : ereport(DEBUG1,
592 : : (errmsg_internal("finished verifying presence of " INT64_FORMAT " tuples from table \"%s\" with bitset %.2f%% set",
593 : : state->heaptuplespresent, RelationGetRelationName(heaprel),
594 : : 100.0 * bloom_prop_bits_set(state->filter))));
595 : :
596 : 73 : bloom_free(state->filter);
597 : : }
598 : :
599 : : /* Be tidy: */
101 alvherre@kurilemu.de 600 [ + + ]: 3963 : if (state->snapshot != InvalidSnapshot)
869 akorotkov@postgresql 601 : 694 : UnregisterSnapshot(state->snapshot);
3293 andres@anarazel.de 602 : 3963 : MemoryContextDelete(state->targetcontext);
603 : 3963 : }
604 : :
605 : : /*
606 : : * Given a left-most block at some level, move right, verifying each page
607 : : * individually (with more verification across pages for "readonly"
608 : : * callers). Caller should pass the true root page as the leftmost initially,
609 : : * working their way down by passing what is returned for the last call here
610 : : * until level 0 (leaf page level) was reached.
611 : : *
612 : : * Returns state for next call, if any. This includes left-most block number
613 : : * one level lower that should be passed on next level/call, which is set to
614 : : * P_NONE on last call here (when leaf level is verified). Level numbers
615 : : * follow the nbtree convention: higher levels have higher numbers, because new
616 : : * levels are added only due to a root page split. Note that prior to the
617 : : * first root page split, the root is also a leaf page, so there is always a
618 : : * level 0 (leaf level), and it's always the last level processed.
619 : : *
620 : : * Note on memory management: State's per-page context is reset here, between
621 : : * each call to bt_target_page_check().
622 : : */
623 : : static BtreeLevel
624 : 2528 : bt_check_level_from_leftmost(BtreeCheckState *state, BtreeLevel level)
625 : : {
626 : : /* State to establish early, concerning entire level */
627 : : BTPageOpaque opaque;
628 : : MemoryContext oldcontext;
629 : : BtreeLevel nextleveldown;
630 : :
631 : : /* Variables for iterating across level using right links */
632 : 2528 : BlockNumber leftcurrent = P_NONE;
633 : 2528 : BlockNumber current = level.leftmost;
634 : :
635 : : /* Initialize return state */
636 : 2528 : nextleveldown.leftmost = InvalidBlockNumber;
637 : 2528 : nextleveldown.level = InvalidBtreeLevel;
638 : 2528 : nextleveldown.istruerootlevel = false;
639 : :
640 : : /* Use page-level context for duration of this call */
641 : 2528 : oldcontext = MemoryContextSwitchTo(state->targetcontext);
642 : :
2165 pg@bowt.ie 643 [ + + + + : 2528 : elog(DEBUG1, "verifying level %u%s", level.level,
+ - ]
644 : : level.istruerootlevel ?
645 : : " (true root level)" : level.level == 0 ? " (leaf level)" : "");
646 : :
2195 akorotkov@postgresql 647 : 2528 : state->prevrightlink = InvalidBlockNumber;
648 : 2528 : state->previncompletesplit = false;
649 : :
650 : : do
651 : : {
652 : : /* Don't rely on CHECK_FOR_INTERRUPTS() calls at lower level */
3293 andres@anarazel.de 653 [ - + ]: 10929 : CHECK_FOR_INTERRUPTS();
654 : :
655 : : /* Initialize state for this iteration */
656 : 10929 : state->targetblock = current;
657 : 10929 : state->target = palloc_btree_page(state, state->targetblock);
658 : 10917 : state->targetlsn = PageGetLSN(state->target);
659 : :
1444 michael@paquier.xyz 660 : 10917 : opaque = BTPageGetOpaque(state->target);
661 : :
3293 andres@anarazel.de 662 [ + + ]: 10917 : if (P_IGNORE(opaque))
663 : : {
664 : : /*
665 : : * Since there cannot be a concurrent VACUUM operation in readonly
666 : : * mode, and since a page has no links within other pages
667 : : * (siblings and parent) once it is marked fully deleted, it
668 : : * should be impossible to land on a fully deleted page in
669 : : * readonly mode. See bt_child_check() for further details.
670 : : *
671 : : * The bt_child_check() P_ISDELETED() check is repeated here so
672 : : * that pages that are only reachable through sibling links get
673 : : * checked.
674 : : */
2881 teodor@sigaev.ru 675 [ + - - + ]:GBC 1 : if (state->readonly && P_ISDELETED(opaque))
2881 teodor@sigaev.ru 676 [ # # ]:UBC 0 : ereport(ERROR,
677 : : (errcode(ERRCODE_INDEX_CORRUPTED),
678 : : errmsg("downlink or sibling link points to deleted block in index \"%s\"",
679 : : RelationGetRelationName(state->rel)),
680 : : errdetail_internal("Block=%u left block=%u left link from block=%u.",
681 : : current, leftcurrent, opaque->btpo_prev)));
682 : :
3293 andres@anarazel.de 683 [ - + ]:GBC 1 : if (P_RIGHTMOST(opaque))
3293 andres@anarazel.de 684 [ # # ]:UBC 0 : ereport(ERROR,
685 : : (errcode(ERRCODE_INDEX_CORRUPTED),
686 : : errmsg("block %u fell off the end of index \"%s\"",
687 : : current, RelationGetRelationName(state->rel))));
688 : : else
3293 andres@anarazel.de 689 [ - + ]:GBC 1 : ereport(DEBUG1,
690 : : (errcode(ERRCODE_NO_DATA),
691 : : errmsg_internal("block %u of index \"%s\" concurrently deleted",
692 : : current, RelationGetRelationName(state->rel))));
693 : 1 : goto nextpage;
694 : : }
3293 andres@anarazel.de 695 [ + + ]:CBC 10916 : else if (nextleveldown.leftmost == InvalidBlockNumber)
696 : : {
697 : : /*
698 : : * A concurrent page split could make the caller supplied leftmost
699 : : * block no longer contain the leftmost page, or no longer be the
700 : : * true root, but where that isn't possible due to heavyweight
701 : : * locking, check that the first valid page meets caller's
702 : : * expectations.
703 : : */
704 [ + + ]: 2516 : if (state->readonly)
705 : : {
867 noah@leadboat.com 706 [ - + ]: 62 : if (!bt_leftmost_ignoring_half_dead(state, current, opaque))
3293 andres@anarazel.de 707 [ # # ]:UBC 0 : ereport(ERROR,
708 : : (errcode(ERRCODE_INDEX_CORRUPTED),
709 : : errmsg("block %u is not leftmost in index \"%s\"",
710 : : current, RelationGetRelationName(state->rel))));
711 : :
103 heikki.linnakangas@i 712 [ + + + + :CBC 62 : if (level.istruerootlevel && (!P_ISROOT(opaque) && !P_INCOMPLETE_SPLIT(opaque)))
- + ]
3293 andres@anarazel.de 713 [ # # ]:UBC 0 : ereport(ERROR,
714 : : (errcode(ERRCODE_INDEX_CORRUPTED),
715 : : errmsg("block %u is not true root in index \"%s\"",
716 : : current, RelationGetRelationName(state->rel))));
717 : : }
718 : :
719 : : /*
720 : : * Before beginning any non-trivial examination of level, prepare
721 : : * state for next bt_check_level_from_leftmost() invocation for
722 : : * the next level for the next level down (if any).
723 : : *
724 : : * There should be at least one non-ignorable page per level,
725 : : * unless this is the leaf level, which is assumed by caller to be
726 : : * final level.
727 : : */
3293 andres@anarazel.de 728 [ + + ]:CBC 2516 : if (!P_ISLEAF(opaque))
729 : : {
730 : : IndexTuple itup;
731 : : ItemId itemid;
732 : :
733 : : /* Internal page -- downlink gets leftmost on next level */
2516 pg@bowt.ie 734 : 565 : itemid = PageGetItemIdCareful(state, state->targetblock,
735 : : state->target,
736 [ + + ]: 565 : P_FIRSTDATAKEY(opaque));
3293 andres@anarazel.de 737 : 565 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2281 pg@bowt.ie 738 : 565 : nextleveldown.leftmost = BTreeTupleGetDownLink(itup);
1845 739 : 565 : nextleveldown.level = opaque->btpo_level - 1;
740 : : }
741 : : else
742 : : {
743 : : /*
744 : : * Leaf page -- final level caller must process.
745 : : *
746 : : * Note that this could also be the root page, if there has
747 : : * been no root page split yet.
748 : : */
3293 andres@anarazel.de 749 : 1951 : nextleveldown.leftmost = P_NONE;
750 : 1951 : nextleveldown.level = InvalidBtreeLevel;
751 : : }
752 : :
753 : : /*
754 : : * Finished setting up state for this call/level. Control will
755 : : * never end up back here in any future loop iteration for this
756 : : * level.
757 : : */
758 : : }
759 : :
760 : : /*
761 : : * Sibling links should be in mutual agreement. There arises
762 : : * leftcurrent == P_NONE && btpo_prev != P_NONE when the left sibling
763 : : * of the parent's low-key downlink is half-dead. (A half-dead page
764 : : * has no downlink from its parent.) Under heavyweight locking, the
765 : : * last bt_leftmost_ignoring_half_dead() validated this btpo_prev.
766 : : * Without heavyweight locking, validation of the P_NONE case remains
767 : : * unimplemented.
768 : : */
867 noah@leadboat.com 769 [ + + - + ]: 10916 : if (opaque->btpo_prev != leftcurrent && leftcurrent != P_NONE)
2045 pg@bowt.ie 770 :UBC 0 : bt_recheck_sibling_links(state, opaque->btpo_prev, leftcurrent);
771 : :
772 : : /* Check level */
1845 pg@bowt.ie 773 [ - + ]:CBC 10916 : if (level.level != opaque->btpo_level)
3293 andres@anarazel.de 774 [ # # ]:UBC 0 : ereport(ERROR,
775 : : (errcode(ERRCODE_INDEX_CORRUPTED),
776 : : errmsg("leftmost down link for level points to block in index \"%s\" whose level is not one level down",
777 : : RelationGetRelationName(state->rel)),
778 : : errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
779 : : current, level.level, opaque->btpo_level)));
780 : :
781 : : /* Verify invariants for page */
3293 andres@anarazel.de 782 :CBC 10916 : bt_target_page_check(state);
783 : :
784 : 10911 : nextpage:
785 : :
786 : : /* Try to detect circular links */
787 [ + - - + ]: 10911 : if (current == leftcurrent || current == opaque->btpo_prev)
3293 andres@anarazel.de 788 [ # # ]:UBC 0 : ereport(ERROR,
789 : : (errcode(ERRCODE_INDEX_CORRUPTED),
790 : : errmsg("circular link chain found in block %u of index \"%s\"",
791 : : current, RelationGetRelationName(state->rel))));
792 : :
2195 akorotkov@postgresql 793 :CBC 10911 : leftcurrent = current;
794 : 10911 : current = opaque->btpo_next;
795 : :
796 [ + + ]: 10911 : if (state->lowkey)
797 : : {
798 [ - + ]: 3456 : Assert(state->readonly);
799 : 3456 : pfree(state->lowkey);
800 : 3456 : state->lowkey = NULL;
801 : : }
802 : :
803 : : /*
804 : : * Copy current target high key as the low key of right sibling.
805 : : * Allocate memory in upper level context, so it would be cleared
806 : : * after reset of target context.
807 : : *
808 : : * We only need the low key in corner cases of checking child high
809 : : * keys. We use high key only when incomplete split on the child level
810 : : * falls to the boundary of pages on the target level. See
811 : : * bt_child_highkey_check() for details. So, typically we won't end
812 : : * up doing anything with low key, but it's simpler for general case
813 : : * high key verification to always have it available.
814 : : *
815 : : * The correctness of managing low key in the case of concurrent
816 : : * splits wasn't investigated yet. Thankfully we only need low key
817 : : * for readonly verification and concurrent splits won't happen.
818 : : */
819 [ + + + + ]: 10911 : if (state->readonly && !P_RIGHTMOST(opaque))
820 : : {
821 : : IndexTuple itup;
822 : : ItemId itemid;
823 : :
824 : 3456 : itemid = PageGetItemIdCareful(state, state->targetblock,
825 : : state->target, P_HIKEY);
826 : 3456 : itup = (IndexTuple) PageGetItem(state->target, itemid);
827 : :
828 : 3456 : state->lowkey = MemoryContextAlloc(oldcontext, IndexTupleSize(itup));
829 : 3456 : memcpy(state->lowkey, itup, IndexTupleSize(itup));
830 : : }
831 : :
832 : : /* Free page and associated memory for this iteration */
3293 andres@anarazel.de 833 : 10911 : MemoryContextReset(state->targetcontext);
834 : : }
835 [ + + ]: 10911 : while (current != P_NONE);
836 : :
2195 akorotkov@postgresql 837 [ - + ]: 2510 : if (state->lowkey)
838 : : {
2195 akorotkov@postgresql 839 [ # # ]:UBC 0 : Assert(state->readonly);
840 : 0 : pfree(state->lowkey);
841 : 0 : state->lowkey = NULL;
842 : : }
843 : :
844 : : /* Don't change context for caller */
3293 andres@anarazel.de 845 :CBC 2510 : MemoryContextSwitchTo(oldcontext);
846 : :
847 : 2510 : return nextleveldown;
848 : : }
849 : :
850 : : /* Check visibility of the table entry referenced by nbtree index */
851 : : static bool
869 akorotkov@postgresql 852 : 324 : heap_entry_is_visible(BtreeCheckState *state, ItemPointer tid)
853 : : {
854 : : bool tid_visible;
855 : :
856 : 324 : TupleTableSlot *slot = table_slot_create(state->heaprel, NULL);
857 : :
858 : 324 : tid_visible = table_tuple_fetch_row_version(state->heaprel,
859 : : tid, state->snapshot, slot);
860 [ + - ]: 324 : if (slot != NULL)
861 : 324 : ExecDropSingleTupleTableSlot(slot);
862 : :
863 : 324 : return tid_visible;
864 : : }
865 : :
866 : : /*
867 : : * Prepare an error message for unique constraint violation in
868 : : * a btree index and report ERROR.
869 : : */
870 : : static void
871 : 3 : bt_report_duplicate(BtreeCheckState *state,
872 : : BtreeLastVisibleEntry *lVis,
873 : : ItemPointer nexttid, BlockNumber nblock, OffsetNumber noffset,
874 : : int nposting)
875 : : {
876 : : char *htid,
877 : : *nhtid,
878 : : *itid,
879 : 3 : *nitid = "",
880 : 3 : *pposting = "",
881 : 3 : *pnposting = "";
882 : :
883 : 3 : htid = psprintf("tid=(%u,%u)",
661 884 : 3 : ItemPointerGetBlockNumberNoCheck(lVis->tid),
885 : 3 : ItemPointerGetOffsetNumberNoCheck(lVis->tid));
869 886 : 3 : nhtid = psprintf("tid=(%u,%u)",
887 : : ItemPointerGetBlockNumberNoCheck(nexttid),
888 : 3 : ItemPointerGetOffsetNumberNoCheck(nexttid));
661 889 : 3 : itid = psprintf("tid=(%u,%u)", lVis->blkno, lVis->offset);
890 : :
891 [ + - + - ]: 3 : if (nblock != lVis->blkno || noffset != lVis->offset)
869 892 : 3 : nitid = psprintf(" tid=(%u,%u)", nblock, noffset);
893 : :
661 894 [ - + ]: 3 : if (lVis->postingIndex >= 0)
661 akorotkov@postgresql 895 :UBC 0 : pposting = psprintf(" posting %u", lVis->postingIndex);
896 : :
869 akorotkov@postgresql 897 [ - + ]:CBC 3 : if (nposting >= 0)
869 akorotkov@postgresql 898 :UBC 0 : pnposting = psprintf(" posting %u", nposting);
899 : :
869 akorotkov@postgresql 900 [ + - ]:CBC 3 : ereport(ERROR,
901 : : (errcode(ERRCODE_INDEX_CORRUPTED),
902 : : errmsg("index uniqueness is violated for index \"%s\"",
903 : : RelationGetRelationName(state->rel)),
904 : : errdetail("Index %s%s and%s%s (point to heap %s and %s) page lsn=%X/%08X.",
905 : : itid, pposting, nitid, pnposting, htid, nhtid,
906 : : LSN_FORMAT_ARGS(state->targetlsn))));
907 : : }
908 : :
909 : : /* Check if current nbtree leaf entry complies with UNIQUE constraint */
910 : : static void
911 : 324 : bt_entry_unique_check(BtreeCheckState *state, IndexTuple itup,
912 : : BlockNumber targetblock, OffsetNumber offset,
913 : : BtreeLastVisibleEntry *lVis)
914 : : {
915 : : ItemPointer tid;
916 : 324 : bool has_visible_entry = false;
917 : :
918 [ - + ]: 324 : Assert(targetblock != P_NONE);
919 : :
920 : : /*
921 : : * Current tuple has posting list. Report duplicate if TID of any posting
922 : : * list entry is visible and lVis->tid is valid.
923 : : */
924 [ - + ]: 324 : if (BTreeTupleIsPosting(itup))
925 : : {
869 akorotkov@postgresql 926 [ # # ]:UBC 0 : for (int i = 0; i < BTreeTupleGetNPosting(itup); i++)
927 : : {
928 : 0 : tid = BTreeTupleGetPostingN(itup, i);
929 [ # # ]: 0 : if (heap_entry_is_visible(state, tid))
930 : : {
931 : 0 : has_visible_entry = true;
661 932 [ # # ]: 0 : if (ItemPointerIsValid(lVis->tid))
933 : : {
869 934 : 0 : bt_report_duplicate(state,
935 : : lVis,
936 : : tid, targetblock,
937 : : offset, i);
938 : : }
939 : :
940 : : /*
941 : : * Prevent double reporting unique constraint violation
942 : : * between the posting list entries of the first tuple on the
943 : : * page after cross-page check.
944 : : */
661 945 [ # # # # ]: 0 : if (lVis->blkno != targetblock && ItemPointerIsValid(lVis->tid))
869 946 : 0 : return;
947 : :
661 948 : 0 : lVis->blkno = targetblock;
949 : 0 : lVis->offset = offset;
950 : 0 : lVis->postingIndex = i;
951 : 0 : lVis->tid = tid;
952 : : }
953 : : }
954 : : }
955 : :
956 : : /*
957 : : * Current tuple has no posting list. If TID is visible save info about it
958 : : * for the next comparisons in the loop in bt_target_page_check(). Report
959 : : * duplicate if lVis->tid is already valid.
960 : : */
961 : : else
962 : : {
869 akorotkov@postgresql 963 :CBC 324 : tid = BTreeTupleGetHeapTID(itup);
964 [ + + ]: 324 : if (heap_entry_is_visible(state, tid))
965 : : {
966 : 12 : has_visible_entry = true;
661 967 [ + + ]: 12 : if (ItemPointerIsValid(lVis->tid))
968 : : {
869 969 : 3 : bt_report_duplicate(state,
970 : : lVis,
971 : : tid, targetblock,
972 : : offset, -1);
973 : : }
974 : :
661 975 : 9 : lVis->blkno = targetblock;
976 : 9 : lVis->offset = offset;
977 : 9 : lVis->tid = tid;
978 : 9 : lVis->postingIndex = -1;
979 : : }
980 : : }
981 : :
982 [ + + ]: 321 : if (!has_visible_entry &&
983 [ + + ]: 312 : lVis->blkno != InvalidBlockNumber &&
984 [ - + ]: 6 : lVis->blkno != targetblock)
985 : : {
869 akorotkov@postgresql 986 :UBC 0 : char *posting = "";
987 : :
661 988 [ # # ]: 0 : if (lVis->postingIndex >= 0)
989 : 0 : posting = psprintf(" posting %u", lVis->postingIndex);
869 990 [ # # ]: 0 : ereport(DEBUG1,
991 : : (errcode(ERRCODE_NO_DATA),
992 : : errmsg("index uniqueness can not be checked for index tid=(%u,%u) in index \"%s\"",
993 : : targetblock, offset,
994 : : RelationGetRelationName(state->rel)),
995 : : errdetail("It doesn't have visible heap tids and key is equal to the tid=(%u,%u)%s (points to heap tid=(%u,%u)).",
996 : : lVis->blkno, lVis->offset, posting,
997 : : ItemPointerGetBlockNumberNoCheck(lVis->tid),
998 : : ItemPointerGetOffsetNumberNoCheck(lVis->tid)),
999 : : errhint("VACUUM the table and repeat the check.")));
1000 : : }
1001 : : }
1002 : :
1003 : : /*
1004 : : * Like P_LEFTMOST(start_opaque), but accept an arbitrarily-long chain of
1005 : : * half-dead, sibling-linked pages to the left. If a half-dead page appears
1006 : : * under state->readonly, the database exited recovery between the first-stage
1007 : : * and second-stage WAL records of a deletion.
1008 : : */
1009 : : static bool
867 noah@leadboat.com 1010 :CBC 83 : bt_leftmost_ignoring_half_dead(BtreeCheckState *state,
1011 : : BlockNumber start,
1012 : : BTPageOpaque start_opaque)
1013 : : {
1014 : 83 : BlockNumber reached = start_opaque->btpo_prev,
1015 : 83 : reached_from = start;
1016 : 83 : bool all_half_dead = true;
1017 : :
1018 : : /*
1019 : : * To handle the !readonly case, we'd need to accept BTP_DELETED pages and
1020 : : * potentially observe nbtree/README "Page deletion and backwards scans".
1021 : : */
1022 [ - + ]: 83 : Assert(state->readonly);
1023 : :
1024 [ + + + - ]: 85 : while (reached != P_NONE && all_half_dead)
1025 : : {
1026 : 2 : Page page = palloc_btree_page(state, reached);
1027 : 2 : BTPageOpaque reached_opaque = BTPageGetOpaque(page);
1028 : :
1029 [ - + ]: 2 : CHECK_FOR_INTERRUPTS();
1030 : :
1031 : : /*
1032 : : * Try to detect btpo_prev circular links. _bt_unlink_halfdead_page()
1033 : : * writes that side-links will continue to point to the siblings.
1034 : : * Check btpo_next for that property.
1035 : : */
1036 [ + - ]: 2 : all_half_dead = P_ISHALFDEAD(reached_opaque) &&
1037 [ + - ]: 2 : reached != start &&
1038 [ + - ]: 4 : reached != reached_from &&
1039 [ + - ]: 2 : reached_opaque->btpo_next == reached_from;
1040 [ + - ]: 2 : if (all_half_dead)
1041 : : {
1042 : 2 : XLogRecPtr pagelsn = PageGetLSN(page);
1043 : :
1044 : : /* pagelsn should point to an XLOG_BTREE_MARK_PAGE_HALFDEAD */
1045 [ + - ]: 2 : ereport(DEBUG1,
1046 : : (errcode(ERRCODE_NO_DATA),
1047 : : errmsg_internal("harmless interrupted page deletion detected in index \"%s\"",
1048 : : RelationGetRelationName(state->rel)),
1049 : : errdetail_internal("Block=%u right block=%u page lsn=%X/%08X.",
1050 : : reached, reached_from,
1051 : : LSN_FORMAT_ARGS(pagelsn))));
1052 : :
1053 : 2 : reached_from = reached;
1054 : 2 : reached = reached_opaque->btpo_prev;
1055 : : }
1056 : :
1057 : 2 : pfree(page);
1058 : : }
1059 : :
1060 : 83 : return all_half_dead;
1061 : : }
1062 : :
1063 : : /*
1064 : : * Raise an error when target page's left link does not point back to the
1065 : : * previous target page, called leftcurrent here. The leftcurrent page's
1066 : : * right link was followed to get to the current target page, and we expect
1067 : : * mutual agreement among leftcurrent and the current target page. Make sure
1068 : : * that this condition has definitely been violated in the !readonly case,
1069 : : * where concurrent page splits are something that we need to deal with.
1070 : : *
1071 : : * Cross-page inconsistencies involving pages that don't agree about being
1072 : : * siblings are known to be a particularly good indicator of corruption
1073 : : * involving partial writes/lost updates. The bt_right_page_check_scankey
1074 : : * check also provides a way of detecting cross-page inconsistencies for
1075 : : * !readonly callers, but it can only detect sibling pages that have an
1076 : : * out-of-order keyspace, which can't catch many of the problems that we
1077 : : * expect to catch here.
1078 : : *
1079 : : * The classic example of the kind of inconsistency that we can only catch
1080 : : * with this check (when in !readonly mode) involves three sibling pages that
1081 : : * were affected by a faulty page split at some point in the past. The
1082 : : * effects of the split are reflected in the original page and its new right
1083 : : * sibling page, with a lack of any accompanying changes for the _original_
1084 : : * right sibling page. The original right sibling page's left link fails to
1085 : : * point to the new right sibling page (its left link still points to the
1086 : : * original page), even though the first phase of a page split is supposed to
1087 : : * work as a single atomic action. This subtle inconsistency will probably
1088 : : * only break backwards scans in practice.
1089 : : *
1090 : : * Note that this is the only place where amcheck will "couple" buffer locks
1091 : : * (and only for !readonly callers). In general we prefer to avoid more
1092 : : * thorough cross-page checks in !readonly mode, but it seems worth the
1093 : : * complexity here. Also, the performance overhead of performing lock
1094 : : * coupling here is negligible in practice. Control only reaches here with a
1095 : : * non-corrupt index when there is a concurrent page split at the instant
1096 : : * caller crossed over to target page from leftcurrent page.
1097 : : */
1098 : : static void
2045 pg@bowt.ie 1099 :UBC 0 : bt_recheck_sibling_links(BtreeCheckState *state,
1100 : : BlockNumber btpo_prev_from_target,
1101 : : BlockNumber leftcurrent)
1102 : : {
1103 : : /* passing metapage to BTPageGetOpaque() would give irrelevant findings */
867 noah@leadboat.com 1104 [ # # ]: 0 : Assert(leftcurrent != P_NONE);
1105 : :
2045 pg@bowt.ie 1106 [ # # ]: 0 : if (!state->readonly)
1107 : : {
1108 : : Buffer lbuf;
1109 : : Buffer newtargetbuf;
1110 : : Page page;
1111 : : BTPageOpaque opaque;
1112 : : BlockNumber newtargetblock;
1113 : :
1114 : : /* Couple locks in the usual order for nbtree: Left to right */
1115 : 0 : lbuf = ReadBufferExtended(state->rel, MAIN_FORKNUM, leftcurrent,
1116 : : RBM_NORMAL, state->checkstrategy);
1117 : 0 : LockBuffer(lbuf, BT_READ);
1118 : 0 : _bt_checkpage(state->rel, lbuf);
1119 : 0 : page = BufferGetPage(lbuf);
1444 michael@paquier.xyz 1120 : 0 : opaque = BTPageGetOpaque(page);
2045 pg@bowt.ie 1121 [ # # ]: 0 : if (P_ISDELETED(opaque))
1122 : : {
1123 : : /*
1124 : : * Cannot reason about concurrently deleted page -- the left link
1125 : : * in the page to the right is expected to point to some other
1126 : : * page to the left (not leftcurrent page).
1127 : : *
1128 : : * Note that we deliberately don't give up with a half-dead page.
1129 : : */
1130 : 0 : UnlockReleaseBuffer(lbuf);
1131 : 0 : return;
1132 : : }
1133 : :
1134 : 0 : newtargetblock = opaque->btpo_next;
1135 : : /* Avoid self-deadlock when newtargetblock == leftcurrent */
1136 [ # # ]: 0 : if (newtargetblock != leftcurrent)
1137 : : {
1138 : 0 : newtargetbuf = ReadBufferExtended(state->rel, MAIN_FORKNUM,
1139 : : newtargetblock, RBM_NORMAL,
1140 : : state->checkstrategy);
1141 : 0 : LockBuffer(newtargetbuf, BT_READ);
1142 : 0 : _bt_checkpage(state->rel, newtargetbuf);
1143 : 0 : page = BufferGetPage(newtargetbuf);
1444 michael@paquier.xyz 1144 : 0 : opaque = BTPageGetOpaque(page);
1145 : : /* btpo_prev_from_target may have changed; update it */
2045 pg@bowt.ie 1146 : 0 : btpo_prev_from_target = opaque->btpo_prev;
1147 : : }
1148 : : else
1149 : : {
1150 : : /*
1151 : : * leftcurrent right sibling points back to leftcurrent block.
1152 : : * Index is corrupt. Easiest way to handle this is to pretend
1153 : : * that we actually read from a distinct page that has an invalid
1154 : : * block number in its btpo_prev.
1155 : : */
1156 : 0 : newtargetbuf = InvalidBuffer;
1157 : 0 : btpo_prev_from_target = InvalidBlockNumber;
1158 : : }
1159 : :
1160 : : /*
1161 : : * No need to check P_ISDELETED here, since new target block cannot be
1162 : : * marked deleted as long as we hold a lock on lbuf
1163 : : */
1164 [ # # ]: 0 : if (BufferIsValid(newtargetbuf))
1165 : 0 : UnlockReleaseBuffer(newtargetbuf);
1166 : 0 : UnlockReleaseBuffer(lbuf);
1167 : :
1168 [ # # ]: 0 : if (btpo_prev_from_target == leftcurrent)
1169 : : {
1170 : : /* Report split in left sibling, not target (or new target) */
1171 [ # # ]: 0 : ereport(DEBUG1,
1172 : : (errcode(ERRCODE_INTERNAL_ERROR),
1173 : : errmsg_internal("harmless concurrent page split detected in index \"%s\"",
1174 : : RelationGetRelationName(state->rel)),
1175 : : errdetail_internal("Block=%u new right sibling=%u original right sibling=%u.",
1176 : : leftcurrent, newtargetblock,
1177 : : state->targetblock)));
1178 : 0 : return;
1179 : : }
1180 : :
1181 : : /*
1182 : : * Index is corrupt. Make sure that we report correct target page.
1183 : : *
1184 : : * This could have changed in cases where there was a concurrent page
1185 : : * split, as well as index corruption (at least in theory). Note that
1186 : : * btpo_prev_from_target was already updated above.
1187 : : */
1188 : 0 : state->targetblock = newtargetblock;
1189 : : }
1190 : :
1191 [ # # ]: 0 : ereport(ERROR,
1192 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1193 : : errmsg("left link/right link pair in index \"%s\" not in agreement",
1194 : : RelationGetRelationName(state->rel)),
1195 : : errdetail_internal("Block=%u left block=%u left link from block=%u.",
1196 : : state->targetblock, leftcurrent,
1197 : : btpo_prev_from_target)));
1198 : : }
1199 : :
1200 : : /*
1201 : : * Function performs the following checks on target page, or pages ancillary to
1202 : : * target page:
1203 : : *
1204 : : * - That every "real" data item is less than or equal to the high key, which
1205 : : * is an upper bound on the items on the page. Data items should be
1206 : : * strictly less than the high key when the page is an internal page.
1207 : : *
1208 : : * - That within the page, every data item is strictly less than the item
1209 : : * immediately to its right, if any (i.e., that the items are in order
1210 : : * within the page, so that the binary searches performed by index scans are
1211 : : * sane).
1212 : : *
1213 : : * - That the last data item stored on the page is strictly less than the
1214 : : * first data item on the page to the right (when such a first item is
1215 : : * available).
1216 : : *
1217 : : * - Various checks on the structure of tuples themselves. For example, check
1218 : : * that non-pivot tuples have no truncated attributes.
1219 : : *
1220 : : * - For index with unique constraint make sure that only one of table entries
1221 : : * for equal keys is visible.
1222 : : *
1223 : : * Furthermore, when state passed shows ShareLock held, function also checks:
1224 : : *
1225 : : * - That all child pages respect strict lower bound from parent's pivot
1226 : : * tuple.
1227 : : *
1228 : : * - That downlink to block was encountered in parent where that's expected.
1229 : : *
1230 : : * - That high keys of child pages matches corresponding pivot keys in parent.
1231 : : *
1232 : : * This is also where heapallindexed callers use their Bloom filter to
1233 : : * fingerprint IndexTuples for later table_index_build_scan() verification.
1234 : : *
1235 : : * Note: Memory allocated in this routine is expected to be released by caller
1236 : : * resetting state->targetcontext.
1237 : : */
1238 : : static void
3293 andres@anarazel.de 1239 :CBC 10916 : bt_target_page_check(BtreeCheckState *state)
1240 : : {
1241 : : OffsetNumber offset;
1242 : : OffsetNumber max;
1243 : : BTPageOpaque topaque;
1244 : :
1245 : : /* Last visible entry info for checking indexes with unique constraint */
661 akorotkov@postgresql 1246 : 10916 : BtreeLastVisibleEntry lVis = {InvalidBlockNumber, InvalidOffsetNumber, -1, NULL};
1247 : :
1444 michael@paquier.xyz 1248 : 10916 : topaque = BTPageGetOpaque(state->target);
3293 andres@anarazel.de 1249 : 10916 : max = PageGetMaxOffsetNumber(state->target);
1250 : :
1251 [ - + - - ]: 10916 : elog(DEBUG2, "verifying %u items on %s block %u", max,
1252 : : P_ISLEAF(topaque) ? "leaf" : "internal", state->targetblock);
1253 : :
1254 : : /*
1255 : : * Check the number of attributes in high key. Note, rightmost page
1256 : : * doesn't contain a high key, so nothing to check
1257 : : */
2516 pg@bowt.ie 1258 [ + + ]: 10916 : if (!P_RIGHTMOST(topaque))
1259 : : {
1260 : : ItemId itemid;
1261 : : IndexTuple itup;
1262 : :
1263 : : /* Verify line pointer before checking tuple */
1264 : 8404 : itemid = PageGetItemIdCareful(state, state->targetblock,
1265 : : state->target, P_HIKEY);
1266 [ - + ]: 8404 : if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
1267 : : P_HIKEY))
1268 : : {
2516 pg@bowt.ie 1269 :UBC 0 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1270 [ # # # # : 0 : ereport(ERROR,
# # ]
1271 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1272 : : errmsg("wrong number of high key index tuple attributes in index \"%s\"",
1273 : : RelationGetRelationName(state->rel)),
1274 : : errdetail_internal("Index block=%u natts=%u block type=%s page lsn=%X/%08X.",
1275 : : state->targetblock,
1276 : : BTreeTupleGetNAtts(itup, state->rel),
1277 : : P_ISLEAF(topaque) ? "heap" : "index",
1278 : : LSN_FORMAT_ARGS(state->targetlsn))));
1279 : : }
1280 : : }
1281 : :
1282 : : /*
1283 : : * Loop over page items, starting from first non-highkey item, not high
1284 : : * key (if any). Most tests are not performed for the "negative infinity"
1285 : : * real item (if any).
1286 : : */
3293 andres@anarazel.de 1287 [ + + ]:CBC 10916 : for (offset = P_FIRSTDATAKEY(topaque);
1288 [ + + ]: 2654552 : offset <= max;
1289 : 2643636 : offset = OffsetNumberNext(offset))
1290 : : {
1291 : : ItemId itemid;
1292 : : IndexTuple itup;
1293 : : size_t tupsize;
1294 : : BTScanInsert skey;
1295 : : bool lowersizelimit;
1296 : : ItemPointer scantid;
1297 : :
1298 : : /*
1299 : : * True if we already called bt_entry_unique_check() for the current
1300 : : * item. This helps to avoid visiting the heap for keys, which are
1301 : : * anyway presented only once and can't comprise a unique violation.
1302 : : */
595 akorotkov@postgresql 1303 : 2643642 : bool unique_checked = false;
1304 : :
3293 andres@anarazel.de 1305 [ - + ]: 2643642 : CHECK_FOR_INTERRUPTS();
1306 : :
2516 pg@bowt.ie 1307 : 2643642 : itemid = PageGetItemIdCareful(state, state->targetblock,
1308 : : state->target, offset);
2906 andres@anarazel.de 1309 : 2643642 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1310 : 2643642 : tupsize = IndexTupleSize(itup);
1311 : :
1312 : : /*
1313 : : * lp_len should match the IndexTuple reported length exactly, since
1314 : : * lp_len is completely redundant in indexes, and both sources of
1315 : : * tuple length are MAXALIGN()'d. nbtree does not use lp_len all that
1316 : : * frequently, and is surprisingly tolerant of corrupt lp_len fields.
1317 : : */
1318 [ - + ]: 2643642 : if (tupsize != ItemIdGetLength(itemid))
2906 andres@anarazel.de 1319 [ # # ]:UBC 0 : ereport(ERROR,
1320 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1321 : : errmsg("index tuple size does not equal lp_len in index \"%s\"",
1322 : : RelationGetRelationName(state->rel)),
1323 : : errdetail_internal("Index tid=(%u,%u) tuple size=%zu lp_len=%u page lsn=%X/%08X.",
1324 : : state->targetblock, offset,
1325 : : tupsize, ItemIdGetLength(itemid),
1326 : : LSN_FORMAT_ARGS(state->targetlsn)),
1327 : : errhint("This could be a torn page problem.")));
1328 : :
1329 : : /* Check the number of index tuple attributes */
2552 pg@bowt.ie 1330 [ - + ]:CBC 2643642 : if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
1331 : : offset))
1332 : : {
1333 : : ItemPointer tid;
1334 : : char *itid,
1335 : : *htid;
1336 : :
2899 teodor@sigaev.ru 1337 :UBC 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
2209 pg@bowt.ie 1338 : 0 : tid = BTreeTupleGetPointsToTID(itup);
2899 teodor@sigaev.ru 1339 : 0 : htid = psprintf("(%u,%u)",
1340 : : ItemPointerGetBlockNumberNoCheck(tid),
2209 pg@bowt.ie 1341 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1342 : :
2899 teodor@sigaev.ru 1343 [ # # # # : 0 : ereport(ERROR,
# # ]
1344 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1345 : : errmsg("wrong number of index tuple attributes in index \"%s\"",
1346 : : RelationGetRelationName(state->rel)),
1347 : : errdetail_internal("Index tid=%s natts=%u points to %s tid=%s page lsn=%X/%08X.",
1348 : : itid,
1349 : : BTreeTupleGetNAtts(itup, state->rel),
1350 : : P_ISLEAF(topaque) ? "heap" : "index",
1351 : : htid,
1352 : : LSN_FORMAT_ARGS(state->targetlsn))));
1353 : : }
1354 : :
1355 : : /*
1356 : : * Don't try to generate scankey using "negative infinity" item on
1357 : : * internal pages. They are always truncated to zero attributes.
1358 : : */
3293 andres@anarazel.de 1359 [ + + ]:CBC 2643642 : if (offset_is_negative_infinity(topaque, offset))
1360 : : {
1361 : : /*
1362 : : * We don't call bt_child_check() for "negative infinity" items.
1363 : : * But if we're performing downlink connectivity check, we do it
1364 : : * for every item including "negative infinity" one.
1365 : : */
2195 akorotkov@postgresql 1366 [ + - + + ]: 571 : if (!P_ISLEAF(topaque) && state->readonly)
1367 : : {
1368 : 26 : bt_child_highkey_check(state,
1369 : : offset,
1370 : : NULL,
1371 : : topaque->btpo_level);
1372 : : }
3293 andres@anarazel.de 1373 : 571 : continue;
1374 : : }
1375 : :
1376 : : /*
1377 : : * Readonly callers may optionally verify that non-pivot tuples can
1378 : : * each be found by an independent search that starts from the root.
1379 : : * Note that we deliberately don't do individual searches for each
1380 : : * TID, since the posting list itself is validated by other checks.
1381 : : */
2552 pg@bowt.ie 1382 [ + + + + ]: 2643071 : if (state->rootdescend && P_ISLEAF(topaque) &&
1383 [ - + ]: 782487 : !bt_rootdescend(state, itup))
1384 : : {
2209 pg@bowt.ie 1385 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1386 : : char *itid,
1387 : : *htid;
1388 : :
2552 1389 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
2209 1390 : 0 : htid = psprintf("(%u,%u)", ItemPointerGetBlockNumber(tid),
1391 : 0 : ItemPointerGetOffsetNumber(tid));
1392 : :
2552 1393 [ # # ]: 0 : ereport(ERROR,
1394 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1395 : : errmsg("could not find tuple using search from root page in index \"%s\"",
1396 : : RelationGetRelationName(state->rel)),
1397 : : errdetail_internal("Index tid=%s points to heap tid=%s page lsn=%X/%08X.",
1398 : : itid, htid,
1399 : : LSN_FORMAT_ARGS(state->targetlsn))));
1400 : : }
1401 : :
1402 : : /*
1403 : : * If tuple is a posting list tuple, make sure posting list TIDs are
1404 : : * in order
1405 : : */
2209 pg@bowt.ie 1406 [ + + ]:CBC 2643071 : if (BTreeTupleIsPosting(itup))
1407 : : {
1408 : : ItemPointerData last;
1409 : : ItemPointer current;
1410 : :
1411 : 11036 : ItemPointerCopy(BTreeTupleGetHeapTID(itup), &last);
1412 : :
1413 [ + + ]: 81529 : for (int i = 1; i < BTreeTupleGetNPosting(itup); i++)
1414 : : {
1415 : :
1416 : 70493 : current = BTreeTupleGetPostingN(itup, i);
1417 : :
1418 [ - + ]: 70493 : if (ItemPointerCompare(current, &last) <= 0)
1419 : : {
2209 pg@bowt.ie 1420 :UBC 0 : char *itid = psprintf("(%u,%u)", state->targetblock, offset);
1421 : :
1422 [ # # ]: 0 : ereport(ERROR,
1423 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1424 : : errmsg_internal("posting list contains misplaced TID in index \"%s\"",
1425 : : RelationGetRelationName(state->rel)),
1426 : : errdetail_internal("Index tid=%s posting list offset=%d page lsn=%X/%08X.",
1427 : : itid, i,
1428 : : LSN_FORMAT_ARGS(state->targetlsn))));
1429 : : }
1430 : :
2209 pg@bowt.ie 1431 :CBC 70493 : ItemPointerCopy(current, &last);
1432 : : }
1433 : : }
1434 : :
1435 : : /* Build insertion scankey for current page offset */
1009 1436 : 2643071 : skey = bt_mkscankey_pivotsearch(state->rel, itup);
1437 : :
1438 : : /*
1439 : : * Make sure tuple size does not exceed the relevant BTREE_VERSION
1440 : : * specific limit.
1441 : : *
1442 : : * BTREE_VERSION 4 (which introduced heapkeyspace rules) requisitioned
1443 : : * a small amount of space from BTMaxItemSize() in order to ensure
1444 : : * that suffix truncation always has enough space to add an explicit
1445 : : * heap TID back to a tuple -- we pessimistically assume that every
1446 : : * newly inserted tuple will eventually need to have a heap TID
1447 : : * appended during a future leaf page split, when the tuple becomes
1448 : : * the basis of the new high key (pivot tuple) for the leaf page.
1449 : : *
1450 : : * Since the reclaimed space is reserved for that purpose, we must not
1451 : : * enforce the slightly lower limit when the extra space has been used
1452 : : * as intended. In other words, there is only a cross-version
1453 : : * difference in the limit on tuple size within leaf pages.
1454 : : *
1455 : : * Still, we're particular about the details within BTREE_VERSION 4
1456 : : * internal pages. Pivot tuples may only use the extra space for its
1457 : : * designated purpose. Enforce the lower limit for pivot tuples when
1458 : : * an explicit heap TID isn't actually present. (In all other cases
1459 : : * suffix truncation is guaranteed to generate a pivot tuple that's no
1460 : : * larger than the firstright tuple provided to it by its caller.)
1461 : : */
2552 1462 [ + - ]: 5286142 : lowersizelimit = skey->heapkeyspace &&
1463 [ + + + + ]: 2643071 : (P_ISLEAF(topaque) || BTreeTupleGetHeapTID(itup) == NULL);
369 1464 [ + + - + ]: 2643071 : if (tupsize > (lowersizelimit ? BTMaxItemSize : BTMaxItemSizeNoHeapTid))
1465 : : {
2209 pg@bowt.ie 1466 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1467 : : char *itid,
1468 : : *htid;
1469 : :
2552 1470 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1471 : 0 : htid = psprintf("(%u,%u)",
1472 : : ItemPointerGetBlockNumberNoCheck(tid),
2209 1473 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1474 : :
2552 1475 [ # # # # ]: 0 : ereport(ERROR,
1476 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1477 : : errmsg("index row size %zu exceeds maximum for index \"%s\"",
1478 : : tupsize, RelationGetRelationName(state->rel)),
1479 : : errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%08X.",
1480 : : itid,
1481 : : P_ISLEAF(topaque) ? "heap" : "index",
1482 : : htid,
1483 : : LSN_FORMAT_ARGS(state->targetlsn))));
1484 : : }
1485 : :
1486 : : /* Fingerprint leaf page tuples (those that point to the heap) */
2906 andres@anarazel.de 1487 [ + + + + :CBC 2643071 : if (state->heapallindexed && P_ISLEAF(topaque) && !ItemIdIsDead(itemid))
+ - ]
1488 : : {
1489 : : IndexTuple norm;
1490 : :
2209 pg@bowt.ie 1491 [ + + ]: 1088396 : if (BTreeTupleIsPosting(itup))
1492 : : {
1493 : : /* Fingerprint all elements as distinct "plain" tuples */
1494 [ + + ]: 27313 : for (int i = 0; i < BTreeTupleGetNPosting(itup); i++)
1495 : : {
1496 : : IndexTuple logtuple;
1497 : :
1498 : 27116 : logtuple = bt_posting_plain_tuple(itup, i);
1499 : 27116 : norm = bt_normalize_tuple(state, logtuple);
1500 : 27116 : bloom_add_element(state->filter, (unsigned char *) norm,
1501 : : IndexTupleSize(norm));
1502 : : /* Be tidy */
1503 [ + + ]: 27116 : if (norm != logtuple)
1504 : 2 : pfree(norm);
1505 : 27116 : pfree(logtuple);
1506 : : }
1507 : : }
1508 : : else
1509 : : {
1510 : 1088199 : norm = bt_normalize_tuple(state, itup);
1511 : 1088199 : bloom_add_element(state->filter, (unsigned char *) norm,
1512 : : IndexTupleSize(norm));
1513 : : /* Be tidy */
1514 [ + + ]: 1088199 : if (norm != itup)
1515 : 1 : pfree(norm);
1516 : : }
1517 : : }
1518 : :
1519 : : /*
1520 : : * * High key check *
1521 : : *
1522 : : * If there is a high key (if this is not the rightmost page on its
1523 : : * entire level), check that high key actually is upper bound on all
1524 : : * page items. If this is a posting list tuple, we'll need to set
1525 : : * scantid to be highest TID in posting list.
1526 : : *
1527 : : * We prefer to check all items against high key rather than checking
1528 : : * just the last and trusting that the operator class obeys the
1529 : : * transitive law (which implies that all previous items also
1530 : : * respected the high key invariant if they pass the item order
1531 : : * check).
1532 : : *
1533 : : * Ideally, we'd compare every item in the index against every other
1534 : : * item in the index, and not trust opclass obedience of the
1535 : : * transitive law to bridge the gap between children and their
1536 : : * grandparents (as well as great-grandparents, and so on). We don't
1537 : : * go to those lengths because that would be prohibitively expensive,
1538 : : * and probably not markedly more effective in practice.
1539 : : *
1540 : : * On the leaf level, we check that the key is <= the highkey.
1541 : : * However, on non-leaf levels we check that the key is < the highkey,
1542 : : * because the high key is "just another separator" rather than a copy
1543 : : * of some existing key item; we expect it to be unique among all keys
1544 : : * on the same level. (Suffix truncation will sometimes produce a
1545 : : * leaf highkey that is an untruncated copy of the lastleft item, but
1546 : : * never any other item, which necessitates weakening the leaf level
1547 : : * check to <=.)
1548 : : *
1549 : : * Full explanation for why a highkey is never truly a copy of another
1550 : : * item from the same level on internal levels:
1551 : : *
1552 : : * While the new left page's high key is copied from the first offset
1553 : : * on the right page during an internal page split, that's not the
1554 : : * full story. In effect, internal pages are split in the middle of
1555 : : * the firstright tuple, not between the would-be lastleft and
1556 : : * firstright tuples: the firstright key ends up on the left side as
1557 : : * left's new highkey, and the firstright downlink ends up on the
1558 : : * right side as right's new "negative infinity" item. The negative
1559 : : * infinity tuple is truncated to zero attributes, so we're only left
1560 : : * with the downlink. In other words, the copying is just an
1561 : : * implementation detail of splitting in the middle of a (pivot)
1562 : : * tuple. (See also: "Notes About Data Representation" in the nbtree
1563 : : * README.)
1564 : : */
1565 : 2643071 : scantid = skey->scantid;
1566 [ + - + + ]: 2643071 : if (state->heapkeyspace && BTreeTupleIsPosting(itup))
1567 : 11036 : skey->scantid = BTreeTupleGetMaxHeapTID(itup);
1568 : :
3293 andres@anarazel.de 1569 [ + + - + ]: 5112316 : if (!P_RIGHTMOST(topaque) &&
2552 pg@bowt.ie 1570 [ + + ]: 2469245 : !(P_ISLEAF(topaque) ? invariant_leq_offset(state, skey, P_HIKEY) :
1571 : 1690 : invariant_l_offset(state, skey, P_HIKEY)))
1572 : : {
2209 pg@bowt.ie 1573 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1574 : : char *itid,
1575 : : *htid;
1576 : :
3293 andres@anarazel.de 1577 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1578 : 0 : htid = psprintf("(%u,%u)",
1579 : : ItemPointerGetBlockNumberNoCheck(tid),
2209 pg@bowt.ie 1580 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1581 : :
3293 andres@anarazel.de 1582 [ # # # # ]: 0 : ereport(ERROR,
1583 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1584 : : errmsg("high key invariant violated for index \"%s\"",
1585 : : RelationGetRelationName(state->rel)),
1586 : : errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%08X.",
1587 : : itid,
1588 : : P_ISLEAF(topaque) ? "heap" : "index",
1589 : : htid,
1590 : : LSN_FORMAT_ARGS(state->targetlsn))));
1591 : : }
1592 : : /* Reset, in case scantid was set to (itup) posting tuple's max TID */
2209 pg@bowt.ie 1593 :CBC 2643071 : skey->scantid = scantid;
1594 : :
1595 : : /*
1596 : : * * Item order check *
1597 : : *
1598 : : * Check that items are stored on page in logical order, by checking
1599 : : * current item is strictly less than next item (if any).
1600 : : */
3293 andres@anarazel.de 1601 [ + + ]: 2643071 : if (OffsetNumberNext(offset) <= max &&
2552 pg@bowt.ie 1602 [ + + ]: 2632164 : !invariant_l_offset(state, skey, OffsetNumberNext(offset)))
1603 : : {
1604 : : ItemPointer tid;
1605 : : char *itid,
1606 : : *htid,
1607 : : *nitid,
1608 : : *nhtid;
1609 : :
3293 andres@anarazel.de 1610 : 3 : itid = psprintf("(%u,%u)", state->targetblock, offset);
2209 pg@bowt.ie 1611 : 3 : tid = BTreeTupleGetPointsToTID(itup);
3293 andres@anarazel.de 1612 : 3 : htid = psprintf("(%u,%u)",
1613 : : ItemPointerGetBlockNumberNoCheck(tid),
2209 pg@bowt.ie 1614 : 3 : ItemPointerGetOffsetNumberNoCheck(tid));
3293 andres@anarazel.de 1615 : 3 : nitid = psprintf("(%u,%u)", state->targetblock,
1616 : 3 : OffsetNumberNext(offset));
1617 : :
1618 : : /* Reuse itup to get pointed-to heap location of second item */
2516 pg@bowt.ie 1619 : 3 : itemid = PageGetItemIdCareful(state, state->targetblock,
1620 : : state->target,
1621 : 3 : OffsetNumberNext(offset));
3293 andres@anarazel.de 1622 : 3 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2209 pg@bowt.ie 1623 : 3 : tid = BTreeTupleGetPointsToTID(itup);
3293 andres@anarazel.de 1624 : 3 : nhtid = psprintf("(%u,%u)",
1625 : : ItemPointerGetBlockNumberNoCheck(tid),
2209 pg@bowt.ie 1626 : 3 : ItemPointerGetOffsetNumberNoCheck(tid));
1627 : :
3293 andres@anarazel.de 1628 [ + - + + : 3 : ereport(ERROR,
+ + ]
1629 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1630 : : errmsg("item order invariant violated for index \"%s\"",
1631 : : RelationGetRelationName(state->rel)),
1632 : : errdetail_internal("Lower index tid=%s (points to %s tid=%s) higher index tid=%s (points to %s tid=%s) page lsn=%X/%08X.",
1633 : : itid,
1634 : : P_ISLEAF(topaque) ? "heap" : "index",
1635 : : htid,
1636 : : nitid,
1637 : : P_ISLEAF(topaque) ? "heap" : "index",
1638 : : nhtid,
1639 : : LSN_FORMAT_ARGS(state->targetlsn))));
1640 : : }
1641 : :
1642 : : /*
1643 : : * If the index is unique verify entries uniqueness by checking the
1644 : : * heap tuples visibility. Immediately check posting tuples and
1645 : : * tuples with repeated keys. Postpone check for keys, which have the
1646 : : * first appearance.
1647 : : */
869 akorotkov@postgresql 1648 [ + + + + ]: 2643068 : if (state->checkunique && state->indexinfo->ii_Unique &&
595 1649 [ + + + + : 303527 : P_ISLEAF(topaque) && !skey->anynullkeys &&
+ - ]
1650 [ + + ]: 302894 : (BTreeTupleIsPosting(itup) || ItemPointerIsValid(lVis.tid)))
1651 : : {
869 1652 : 9 : bt_entry_unique_check(state, itup, state->targetblock, offset,
1653 : : &lVis);
595 1654 : 6 : unique_checked = true;
1655 : : }
1656 : :
869 1657 [ + + + + ]: 2643065 : if (state->checkunique && state->indexinfo->ii_Unique &&
1658 [ + + + + ]: 152077 : P_ISLEAF(topaque) && OffsetNumberNext(offset) <= max)
1659 : : {
1660 : : /* Save current scankey tid */
1661 : 150685 : scantid = skey->scantid;
1662 : :
1663 : : /*
1664 : : * Invalidate scankey tid to make _bt_compare compare only keys in
1665 : : * the item to report equality even if heap TIDs are different
1666 : : */
1667 : 150685 : skey->scantid = NULL;
1668 : :
1669 : : /*
1670 : : * If next key tuple is different, invalidate last visible entry
1671 : : * data (whole index tuple or last posting in index tuple). Key
1672 : : * containing null value does not violate unique constraint and
1673 : : * treated as different to any other key.
1674 : : *
1675 : : * If the next key is the same as the previous one, do the
1676 : : * bt_entry_unique_check() call if it was postponed.
1677 : : */
1678 [ + + ]: 150685 : if (_bt_compare(state->rel, skey, state->target,
1679 [ + + ]: 151070 : OffsetNumberNext(offset)) != 0 || skey->anynullkeys)
1680 : : {
661 1681 : 150370 : lVis.blkno = InvalidBlockNumber;
1682 : 150370 : lVis.offset = InvalidOffsetNumber;
1683 : 150370 : lVis.postingIndex = -1;
1684 : 150370 : lVis.tid = NULL;
1685 : : }
595 1686 [ + - ]: 315 : else if (!unique_checked)
1687 : : {
1688 : 315 : bt_entry_unique_check(state, itup, state->targetblock, offset,
1689 : : &lVis);
1690 : : }
869 1691 : 150685 : skey->scantid = scantid; /* Restore saved scan key state */
1692 : : }
1693 : :
1694 : : /*
1695 : : * * Last item check *
1696 : : *
1697 : : * Check last item against next/right page's first data item's when
1698 : : * last item on page is reached. This additional check will detect
1699 : : * transposed pages iff the supposed right sibling page happens to
1700 : : * belong before target in the key space. (Otherwise, a subsequent
1701 : : * heap verification will probably detect the problem.)
1702 : : *
1703 : : * This check is similar to the item order check that will have
1704 : : * already been performed for every other "real" item on target page
1705 : : * when last item is checked. The difference is that the next item
1706 : : * (the item that is compared to target's last item) needs to come
1707 : : * from the next/sibling page. There may not be such an item
1708 : : * available from sibling for various reasons, though (e.g., target is
1709 : : * the rightmost page on level).
1710 : : */
1711 [ + + ]: 2643065 : if (offset == max)
1712 : : {
1713 : : BTScanInsert rightkey;
1714 : :
1715 : : /* first offset on a right index page (log only) */
1716 : 10907 : OffsetNumber rightfirstoffset = InvalidOffsetNumber;
1717 : :
1718 : : /* Get item in next/right page */
1719 : 10907 : rightkey = bt_right_page_check_scankey(state, &rightfirstoffset);
1720 : :
3293 andres@anarazel.de 1721 [ + + ]: 10907 : if (rightkey &&
2552 pg@bowt.ie 1722 [ - + ]: 8398 : !invariant_g_offset(state, rightkey, max))
1723 : : {
1724 : : /*
1725 : : * As explained at length in bt_right_page_check_scankey(),
1726 : : * there is a known !readonly race that could account for
1727 : : * apparent violation of invariant, which we must check for
1728 : : * before actually proceeding with raising error. Our canary
1729 : : * condition is that target page was deleted.
1730 : : */
3293 andres@anarazel.de 1731 [ # # ]:UBC 0 : if (!state->readonly)
1732 : : {
1733 : : /* Get fresh copy of target page */
1734 : 0 : state->target = palloc_btree_page(state, state->targetblock);
1735 : : /* Note that we deliberately do not update target LSN */
1444 michael@paquier.xyz 1736 : 0 : topaque = BTPageGetOpaque(state->target);
1737 : :
1738 : : /*
1739 : : * All !readonly checks now performed; just return
1740 : : */
3293 andres@anarazel.de 1741 [ # # ]: 0 : if (P_IGNORE(topaque))
1742 : 0 : return;
1743 : : }
1744 : :
1745 [ # # ]: 0 : ereport(ERROR,
1746 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1747 : : errmsg("cross page item order invariant violated for index \"%s\"",
1748 : : RelationGetRelationName(state->rel)),
1749 : : errdetail_internal("Last item on page tid=(%u,%u) page lsn=%X/%08X.",
1750 : : state->targetblock, offset,
1751 : : LSN_FORMAT_ARGS(state->targetlsn))));
1752 : : }
1753 : :
1754 : : /*
1755 : : * If index has unique constraint make sure that no more than one
1756 : : * found equal items is visible.
1757 : : */
869 akorotkov@postgresql 1758 [ + + + + :CBC 10907 : if (state->checkunique && state->indexinfo->ii_Unique &&
+ + ]
661 1759 [ + - + - ]: 551 : rightkey && P_ISLEAF(topaque) && !P_RIGHTMOST(topaque))
1760 : : {
1761 : 551 : BlockNumber rightblock_number = topaque->btpo_next;
1762 : :
869 1763 [ - + ]: 551 : elog(DEBUG2, "check cross page unique condition");
1764 : :
1765 : : /*
1766 : : * Make _bt_compare compare only index keys without heap TIDs.
1767 : : * rightkey->scantid is modified destructively but it is ok
1768 : : * for it is not used later.
1769 : : */
1770 : 551 : rightkey->scantid = NULL;
1771 : :
1772 : : /* The first key on the next page is the same */
595 1773 [ + + ]: 551 : if (_bt_compare(state->rel, rightkey, state->target, max) == 0 &&
1774 [ - + ]: 7 : !rightkey->anynullkeys)
1775 : : {
1776 : : Page rightpage;
1777 : :
1778 : : /*
1779 : : * Do the bt_entry_unique_check() call if it was
1780 : : * postponed.
1781 : : */
595 akorotkov@postgresql 1782 [ # # ]:UBC 0 : if (!unique_checked)
1783 : 0 : bt_entry_unique_check(state, itup, state->targetblock,
1784 : : offset, &lVis);
1785 : :
869 1786 [ # # ]: 0 : elog(DEBUG2, "cross page equal keys");
661 1787 : 0 : rightpage = palloc_btree_page(state,
1788 : : rightblock_number);
1789 : 0 : topaque = BTPageGetOpaque(rightpage);
1790 : :
1791 [ # # ]: 0 : if (P_IGNORE(topaque))
1792 : : {
658 1793 : 0 : pfree(rightpage);
1794 : 0 : break;
1795 : : }
1796 : :
1797 [ # # ]: 0 : if (unlikely(!P_ISLEAF(topaque)))
1798 [ # # ]: 0 : ereport(ERROR,
1799 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1800 : : errmsg("right block of leaf block is non-leaf for index \"%s\"",
1801 : : RelationGetRelationName(state->rel)),
1802 : : errdetail_internal("Block=%u page lsn=%X/%08X.",
1803 : : state->targetblock,
1804 : : LSN_FORMAT_ARGS(state->targetlsn))));
1805 : :
869 1806 : 0 : itemid = PageGetItemIdCareful(state, rightblock_number,
1807 : : rightpage,
1808 : : rightfirstoffset);
661 1809 : 0 : itup = (IndexTuple) PageGetItem(rightpage, itemid);
1810 : :
1811 : 0 : bt_entry_unique_check(state, itup, rightblock_number, rightfirstoffset, &lVis);
1812 : :
1813 : 0 : pfree(rightpage);
1814 : : }
1815 : : }
1816 : : }
1817 : :
1818 : : /*
1819 : : * * Downlink check *
1820 : : *
1821 : : * Additional check of child items iff this is an internal page and
1822 : : * caller holds a ShareLock. This happens for every downlink (item)
1823 : : * in target excluding the negative-infinity downlink (again, this is
1824 : : * because it has no useful value to compare).
1825 : : */
3293 andres@anarazel.de 1826 [ + + + + ]:CBC 2643065 : if (!P_ISLEAF(topaque) && state->readonly)
2195 akorotkov@postgresql 1827 : 3448 : bt_child_check(state, skey, offset);
1828 : : }
1829 : :
1830 : : /*
1831 : : * Special case bt_child_highkey_check() call
1832 : : *
1833 : : * We don't pass a real downlink, but we've to finish the level
1834 : : * processing. If condition is satisfied, we've already processed all the
1835 : : * downlinks from the target level. But there still might be pages to the
1836 : : * right of the child page pointer to by our rightmost downlink. And they
1837 : : * might have missing downlinks. This final call checks for them.
1838 : : */
1839 [ + + + + : 10910 : if (!P_ISLEAF(topaque) && P_RIGHTMOST(topaque) && state->readonly)
+ + ]
1840 : : {
1841 : 21 : bt_child_highkey_check(state, InvalidOffsetNumber,
1842 : : NULL, topaque->btpo_level);
1843 : : }
1844 : : }
1845 : :
1846 : : /*
1847 : : * Return a scankey for an item on page to right of current target (or the
1848 : : * first non-ignorable page), sufficient to check ordering invariant on last
1849 : : * item in current target page. Returned scankey relies on local memory
1850 : : * allocated for the child page, which caller cannot pfree(). Caller's memory
1851 : : * context should be reset between calls here.
1852 : : *
1853 : : * This is the first data item, and so all adjacent items are checked against
1854 : : * their immediate sibling item (which may be on a sibling page, or even a
1855 : : * "cousin" page at parent boundaries where target's rightlink points to page
1856 : : * with different parent page). If no such valid item is available, return
1857 : : * NULL instead.
1858 : : *
1859 : : * Note that !readonly callers must reverify that target page has not
1860 : : * been concurrently deleted.
1861 : : *
1862 : : * Save rightfirstoffset for detailed error message.
1863 : : */
1864 : : static BTScanInsert
869 1865 : 10907 : bt_right_page_check_scankey(BtreeCheckState *state, OffsetNumber *rightfirstoffset)
1866 : : {
1867 : : BTPageOpaque opaque;
1868 : : ItemId rightitem;
1869 : : IndexTuple firstitup;
1870 : : BlockNumber targetnext;
1871 : : Page rightpage;
1872 : : OffsetNumber nline;
1873 : :
1874 : : /* Determine target's next block number */
1444 michael@paquier.xyz 1875 : 10907 : opaque = BTPageGetOpaque(state->target);
1876 : :
1877 : : /* If target is already rightmost, no right sibling; nothing to do here */
3293 andres@anarazel.de 1878 [ + + ]: 10907 : if (P_RIGHTMOST(opaque))
1879 : 2508 : return NULL;
1880 : :
1881 : : /*
1882 : : * General notes on concurrent page splits and page deletion:
1883 : : *
1884 : : * Routines like _bt_search() don't require *any* page split interlock
1885 : : * when descending the tree, including something very light like a buffer
1886 : : * pin. That's why it's okay that we don't either. This avoidance of any
1887 : : * need to "couple" buffer locks is the raison d' etre of the Lehman & Yao
1888 : : * algorithm, in fact.
1889 : : *
1890 : : * That leaves deletion. A deleted page won't actually be recycled by
1891 : : * VACUUM early enough for us to fail to at least follow its right link
1892 : : * (or left link, or downlink) and find its sibling, because recycling
1893 : : * does not occur until no possible index scan could land on the page.
1894 : : * Index scans can follow links with nothing more than their snapshot as
1895 : : * an interlock and be sure of at least that much. (See page
1896 : : * recycling/"visible to everyone" notes in nbtree README.)
1897 : : *
1898 : : * Furthermore, it's okay if we follow a rightlink and find a half-dead or
1899 : : * dead (ignorable) page one or more times. There will either be a
1900 : : * further right link to follow that leads to a live page before too long
1901 : : * (before passing by parent's rightmost child), or we will find the end
1902 : : * of the entire level instead (possible when parent page is itself the
1903 : : * rightmost on its level).
1904 : : */
1905 : 8399 : targetnext = opaque->btpo_next;
1906 : : for (;;)
1907 : : {
1908 [ - + ]: 8400 : CHECK_FOR_INTERRUPTS();
1909 : :
1910 : 8400 : rightpage = palloc_btree_page(state, targetnext);
1444 michael@paquier.xyz 1911 : 8400 : opaque = BTPageGetOpaque(rightpage);
1912 : :
3293 andres@anarazel.de 1913 [ + + + - ]: 8400 : if (!P_IGNORE(opaque) || P_RIGHTMOST(opaque))
1914 : : break;
1915 : :
1916 : : /*
1917 : : * We landed on a deleted or half-dead sibling page. Step right until
1918 : : * we locate a live sibling page.
1919 : : */
1825 pg@bowt.ie 1920 [ - + ]:GBC 1 : ereport(DEBUG2,
1921 : : (errcode(ERRCODE_NO_DATA),
1922 : : errmsg_internal("level %u sibling page in block %u of index \"%s\" was found deleted or half dead",
1923 : : opaque->btpo_level, targetnext, RelationGetRelationName(state->rel)),
1924 : : errdetail_internal("Deleted page found when building scankey from right sibling.")));
1925 : :
1926 : 1 : targetnext = opaque->btpo_next;
1927 : :
1928 : : /* Be slightly more pro-active in freeing this memory, just in case */
3293 andres@anarazel.de 1929 : 1 : pfree(rightpage);
1930 : : }
1931 : :
1932 : : /*
1933 : : * No ShareLock held case -- why it's safe to proceed.
1934 : : *
1935 : : * Problem:
1936 : : *
1937 : : * We must avoid false positive reports of corruption when caller treats
1938 : : * item returned here as an upper bound on target's last item. In
1939 : : * general, false positives are disallowed. Avoiding them here when
1940 : : * caller is !readonly is subtle.
1941 : : *
1942 : : * A concurrent page deletion by VACUUM of the target page can result in
1943 : : * the insertion of items on to this right sibling page that would
1944 : : * previously have been inserted on our target page. There might have
1945 : : * been insertions that followed the target's downlink after it was made
1946 : : * to point to right sibling instead of target by page deletion's first
1947 : : * phase. The inserters insert items that would belong on target page.
1948 : : * This race is very tight, but it's possible. This is our only problem.
1949 : : *
1950 : : * Non-problems:
1951 : : *
1952 : : * We are not hindered by a concurrent page split of the target; we'll
1953 : : * never land on the second half of the page anyway. A concurrent split
1954 : : * of the right page will also not matter, because the first data item
1955 : : * remains the same within the left half, which we'll reliably land on. If
1956 : : * we had to skip over ignorable/deleted pages, it cannot matter because
1957 : : * their key space has already been atomically merged with the first
1958 : : * non-ignorable page we eventually find (doesn't matter whether the page
1959 : : * we eventually find is a true sibling or a cousin of target, which we go
1960 : : * into below).
1961 : : *
1962 : : * Solution:
1963 : : *
1964 : : * Caller knows that it should reverify that target is not ignorable
1965 : : * (half-dead or deleted) when cross-page sibling item comparison appears
1966 : : * to indicate corruption (invariant fails). This detects the single race
1967 : : * condition that exists for caller. This is correct because the
1968 : : * continued existence of target block as non-ignorable (not half-dead or
1969 : : * deleted) implies that target page was not merged into from the right by
1970 : : * deletion; the key space at or after target never moved left. Target's
1971 : : * parent either has the same downlink to target as before, or a <
1972 : : * downlink due to deletion at the left of target. Target either has the
1973 : : * same highkey as before, or a highkey < before when there is a page
1974 : : * split. (The rightmost concurrently-split-from-target-page page will
1975 : : * still have the same highkey as target was originally found to have,
1976 : : * which for our purposes is equivalent to target's highkey itself never
1977 : : * changing, since we reliably skip over
1978 : : * concurrently-split-from-target-page pages.)
1979 : : *
1980 : : * In simpler terms, we allow that the key space of the target may expand
1981 : : * left (the key space can move left on the left side of target only), but
1982 : : * the target key space cannot expand right and get ahead of us without
1983 : : * our detecting it. The key space of the target cannot shrink, unless it
1984 : : * shrinks to zero due to the deletion of the original page, our canary
1985 : : * condition. (To be very precise, we're a bit stricter than that because
1986 : : * it might just have been that the target page split and only the
1987 : : * original target page was deleted. We can be more strict, just not more
1988 : : * lax.)
1989 : : *
1990 : : * Top level tree walk caller moves on to next page (makes it the new
1991 : : * target) following recovery from this race. (cf. The rationale for
1992 : : * child/downlink verification needing a ShareLock within
1993 : : * bt_child_check(), where page deletion is also the main source of
1994 : : * trouble.)
1995 : : *
1996 : : * Note that it doesn't matter if right sibling page here is actually a
1997 : : * cousin page, because in order for the key space to be readjusted in a
1998 : : * way that causes us issues in next level up (guiding problematic
1999 : : * concurrent insertions to the cousin from the grandparent rather than to
2000 : : * the sibling from the parent), there'd have to be page deletion of
2001 : : * target's parent page (affecting target's parent's downlink in target's
2002 : : * grandparent page). Internal page deletion only occurs when there are
2003 : : * no child pages (they were all fully deleted), and caller is checking
2004 : : * that the target's parent has at least one non-deleted (so
2005 : : * non-ignorable) child: the target page. (Note that the first phase of
2006 : : * deletion atomically marks the page to be deleted half-dead/ignorable at
2007 : : * the same time downlink in its parent is removed, so caller will
2008 : : * definitely not fail to detect that this happened.)
2009 : : *
2010 : : * This trick is inspired by the method backward scans use for dealing
2011 : : * with concurrent page splits; concurrent page deletion is a problem that
2012 : : * similarly receives special consideration sometimes (it's possible that
2013 : : * the backwards scan will re-read its "original" block after failing to
2014 : : * find a right-link to it, having already moved in the opposite direction
2015 : : * (right/"forwards") a few times to try to locate one). Just like us,
2016 : : * that happens only to determine if there was a concurrent page deletion
2017 : : * of a reference page, and just like us if there was a page deletion of
2018 : : * that reference page it means we can move on from caring about the
2019 : : * reference page. See the nbtree README for a full description of how
2020 : : * that works.
2021 : : */
3293 andres@anarazel.de 2022 :CBC 8399 : nline = PageGetMaxOffsetNumber(rightpage);
2023 : :
2024 : : /*
2025 : : * Get first data item, if any
2026 : : */
2027 [ + + + + : 8399 : if (P_ISLEAF(opaque) && nline >= P_FIRSTDATAKEY(opaque))
+ + ]
2028 : : {
2029 : : /* Return first data item (if any) */
2516 pg@bowt.ie 2030 : 8392 : rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
2031 [ + + ]: 8392 : P_FIRSTDATAKEY(opaque));
869 akorotkov@postgresql 2032 [ + + ]: 8392 : *rightfirstoffset = P_FIRSTDATAKEY(opaque);
2033 : : }
3293 andres@anarazel.de 2034 [ + + + - ]: 13 : else if (!P_ISLEAF(opaque) &&
2035 [ + - ]: 6 : nline >= OffsetNumberNext(P_FIRSTDATAKEY(opaque)))
2036 : : {
2037 : : /*
2038 : : * Return first item after the internal page's "negative infinity"
2039 : : * item
2040 : : */
2516 pg@bowt.ie 2041 : 6 : rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
2042 [ + - ]: 6 : OffsetNumberNext(P_FIRSTDATAKEY(opaque)));
2043 : : }
2044 : : else
2045 : : {
2046 : : /*
2047 : : * No first item. Page is probably empty leaf page, but it's also
2048 : : * possible that it's an internal page with only a negative infinity
2049 : : * item.
2050 : : */
1825 pg@bowt.ie 2051 [ - + - - ]:GBC 1 : ereport(DEBUG2,
2052 : : (errcode(ERRCODE_NO_DATA),
2053 : : errmsg_internal("%s block %u of index \"%s\" has no first data item",
2054 : : P_ISLEAF(opaque) ? "leaf" : "internal", targetnext,
2055 : : RelationGetRelationName(state->rel))));
3293 andres@anarazel.de 2056 : 1 : return NULL;
2057 : : }
2058 : :
2059 : : /*
2060 : : * Return first real item scankey. Note that this relies on right page
2061 : : * memory remaining allocated.
2062 : : */
2552 pg@bowt.ie 2063 :CBC 8398 : firstitup = (IndexTuple) PageGetItem(rightpage, rightitem);
1009 2064 : 8398 : return bt_mkscankey_pivotsearch(state->rel, firstitup);
2065 : : }
2066 : :
2067 : : /*
2068 : : * Check if two tuples are binary identical except the block number. So,
2069 : : * this function is capable to compare pivot keys on different levels.
2070 : : */
2071 : : static bool
2006 2072 : 3453 : bt_pivot_tuple_identical(bool heapkeyspace, IndexTuple itup1, IndexTuple itup2)
2073 : : {
2195 akorotkov@postgresql 2074 [ - + ]: 3453 : if (IndexTupleSize(itup1) != IndexTupleSize(itup2))
2195 akorotkov@postgresql 2075 :UBC 0 : return false;
2076 : :
2006 pg@bowt.ie 2077 [ + - ]:CBC 3453 : if (heapkeyspace)
2078 : : {
2079 : : /*
2080 : : * Offset number will contain important information in heapkeyspace
2081 : : * indexes: the number of attributes left in the pivot tuple following
2082 : : * suffix truncation. Don't skip over it (compare it too).
2083 : : */
2084 [ - + ]: 3453 : if (memcmp(&itup1->t_tid.ip_posid, &itup2->t_tid.ip_posid,
2085 : 3453 : IndexTupleSize(itup1) -
2086 : : offsetof(ItemPointerData, ip_posid)) != 0)
2006 pg@bowt.ie 2087 :UBC 0 : return false;
2088 : : }
2089 : : else
2090 : : {
2091 : : /*
2092 : : * Cannot rely on offset number field having consistent value across
2093 : : * levels on pg_upgrade'd !heapkeyspace indexes. Compare contents of
2094 : : * tuple starting from just after item pointer (i.e. after block
2095 : : * number and offset number).
2096 : : */
2097 [ # # ]: 0 : if (memcmp(&itup1->t_info, &itup2->t_info,
2098 : 0 : IndexTupleSize(itup1) -
2099 : : offsetof(IndexTupleData, t_info)) != 0)
2100 : 0 : return false;
2101 : : }
2102 : :
2195 akorotkov@postgresql 2103 :CBC 3453 : return true;
2104 : : }
2105 : :
2106 : : /*---
2107 : : * Check high keys on the child level. Traverse rightlinks from previous
2108 : : * downlink to the current one. Check that there are no intermediate pages
2109 : : * with missing downlinks.
2110 : : *
2111 : : * If 'loaded_child' is given, it's assumed to be the page pointed to by the
2112 : : * downlink referenced by 'downlinkoffnum' of the target page.
2113 : : *
2114 : : * Basically this function is called for each target downlink and checks two
2115 : : * invariants:
2116 : : *
2117 : : * 1) You can reach the next child from previous one via rightlinks;
2118 : : * 2) Each child high key have matching pivot key on target level.
2119 : : *
2120 : : * Consider the sample tree picture.
2121 : : *
2122 : : * 1
2123 : : * / \
2124 : : * 2 <-> 3
2125 : : * / \ / \
2126 : : * 4 <> 5 <> 6 <> 7 <> 8
2127 : : *
2128 : : * This function will be called for blocks 4, 5, 6 and 8. Consider what is
2129 : : * happening for each function call.
2130 : : *
2131 : : * - The function call for block 4 initializes data structure and matches high
2132 : : * key of block 4 to downlink's pivot key of block 2.
2133 : : * - The high key of block 5 is matched to the high key of block 2.
2134 : : * - The block 6 has an incomplete split flag set, so its high key isn't
2135 : : * matched to anything.
2136 : : * - The function call for block 8 checks that block 8 can be found while
2137 : : * following rightlinks from block 6. The high key of block 7 will be
2138 : : * matched to downlink's pivot key in block 3.
2139 : : *
2140 : : * There is also final call of this function, which checks that there is no
2141 : : * missing downlinks for children to the right of the child referenced by
2142 : : * rightmost downlink in target level.
2143 : : */
2144 : : static void
2145 : 3495 : bt_child_highkey_check(BtreeCheckState *state,
2146 : : OffsetNumber target_downlinkoffnum,
2147 : : Page loaded_child,
2148 : : uint32 target_level)
2149 : : {
2150 : 3495 : BlockNumber blkno = state->prevrightlink;
2151 : : Page page;
2152 : : BTPageOpaque opaque;
2153 : 3495 : bool rightsplit = state->previncompletesplit;
2154 : 3495 : bool first = true;
2155 : : ItemId itemid;
2156 : : IndexTuple itup;
2157 : : BlockNumber downlink;
2158 : :
2159 [ + + + - : 3495 : if (OffsetNumberIsValid(target_downlinkoffnum))
+ + ]
2160 : : {
2161 : 3474 : itemid = PageGetItemIdCareful(state, state->targetblock,
2162 : : state->target, target_downlinkoffnum);
2163 : 3474 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2164 : 3474 : downlink = BTreeTupleGetDownLink(itup);
2165 : : }
2166 : : else
2167 : : {
2168 : 21 : downlink = P_NONE;
2169 : : }
2170 : :
2171 : : /*
2172 : : * If no previous rightlink is memorized for current level just below
2173 : : * target page's level, we are about to start from the leftmost page. We
2174 : : * can't follow rightlinks from previous page, because there is no
2175 : : * previous page. But we still can match high key.
2176 : : *
2177 : : * So we initialize variables for the loop above like there is previous
2178 : : * page referencing current child. Also we imply previous page to not
2179 : : * have incomplete split flag, that would make us require downlink for
2180 : : * current child. That's correct, because leftmost page on the level
2181 : : * should always have parent downlink.
2182 : : */
2183 [ + + ]: 3495 : if (!BlockNumberIsValid(blkno))
2184 : : {
2185 : 21 : blkno = downlink;
2186 : 21 : rightsplit = false;
2187 : : }
2188 : :
2189 : : /* Move to the right on the child level */
2190 : : while (true)
2191 : : {
2192 : : /*
2193 : : * Did we traverse the whole tree level and this is check for pages to
2194 : : * the right of rightmost downlink?
2195 : : */
2196 [ + + + - ]: 3497 : if (blkno == P_NONE && downlink == P_NONE)
2197 : : {
2198 : 21 : state->prevrightlink = InvalidBlockNumber;
2199 : 21 : state->previncompletesplit = false;
2200 : 21 : return;
2201 : : }
2202 : :
2203 : : /* Did we traverse the whole tree level and don't find next downlink? */
2204 [ - + ]: 3476 : if (blkno == P_NONE)
2195 akorotkov@postgresql 2205 [ # # ]:UBC 0 : ereport(ERROR,
2206 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2207 : : errmsg("can't traverse from downlink %u to downlink %u of index \"%s\"",
2208 : : state->prevrightlink, downlink,
2209 : : RelationGetRelationName(state->rel))));
2210 : :
2211 : : /* Load page contents */
2195 akorotkov@postgresql 2212 [ + + + + ]:CBC 3476 : if (blkno == downlink && loaded_child)
2213 : 3448 : page = loaded_child;
2214 : : else
2215 : 28 : page = palloc_btree_page(state, blkno);
2216 : :
1444 michael@paquier.xyz 2217 : 3476 : opaque = BTPageGetOpaque(page);
2218 : :
2219 : : /* The first page we visit at the level should be leftmost */
867 noah@leadboat.com 2220 [ + + + + ]: 3476 : if (first && !BlockNumberIsValid(state->prevrightlink) &&
2221 [ - + ]: 21 : !bt_leftmost_ignoring_half_dead(state, blkno, opaque))
2195 akorotkov@postgresql 2222 [ # # ]:UBC 0 : ereport(ERROR,
2223 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2224 : : errmsg("the first child of leftmost target page is not leftmost of its level in index \"%s\"",
2225 : : RelationGetRelationName(state->rel)),
2226 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%08X.",
2227 : : state->targetblock, blkno,
2228 : : LSN_FORMAT_ARGS(state->targetlsn))));
2229 : :
2230 : : /* Do level sanity check */
1845 pg@bowt.ie 2231 [ - + - - ]:CBC 3476 : if ((!P_ISDELETED(opaque) || P_HAS_FULLXID(opaque)) &&
2232 [ - + ]: 3476 : opaque->btpo_level != target_level - 1)
2195 akorotkov@postgresql 2233 [ # # ]:UBC 0 : ereport(ERROR,
2234 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2235 : : errmsg("block found while following rightlinks from child of index \"%s\" has invalid level",
2236 : : RelationGetRelationName(state->rel)),
2237 : : errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
2238 : : blkno, target_level - 1, opaque->btpo_level)));
2239 : :
2240 : : /* Try to detect circular links */
2195 akorotkov@postgresql 2241 [ + + + - :CBC 3476 : if ((!first && blkno == state->prevrightlink) || blkno == opaque->btpo_prev)
- + ]
2195 akorotkov@postgresql 2242 [ # # ]:UBC 0 : ereport(ERROR,
2243 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2244 : : errmsg("circular link chain found in block %u of index \"%s\"",
2245 : : blkno, RelationGetRelationName(state->rel))));
2246 : :
2195 akorotkov@postgresql 2247 [ + + + + ]:CBC 3476 : if (blkno != downlink && !P_IGNORE(opaque))
2248 : : {
2249 : : /* blkno probably has missing parent downlink */
2195 akorotkov@postgresql 2250 :GBC 1 : bt_downlink_missing_check(state, rightsplit, blkno, page);
2251 : : }
2252 : :
2195 akorotkov@postgresql 2253 :CBC 3476 : rightsplit = P_INCOMPLETE_SPLIT(opaque);
2254 : :
2255 : : /*
2256 : : * If we visit page with high key, check that it is equal to the
2257 : : * target key next to corresponding downlink.
2258 : : */
103 heikki.linnakangas@i 2259 [ + + + + : 3476 : if (!rightsplit && !P_RIGHTMOST(opaque) && !P_ISHALFDEAD(opaque))
+ + ]
2260 : : {
2261 : : BTPageOpaque topaque;
2262 : : IndexTuple highkey;
2263 : : OffsetNumber pivotkey_offset;
2264 : :
2265 : : /* Get high key */
2195 akorotkov@postgresql 2266 : 3453 : itemid = PageGetItemIdCareful(state, blkno, page, P_HIKEY);
2267 : 3453 : highkey = (IndexTuple) PageGetItem(page, itemid);
2268 : :
2269 : : /*
2270 : : * There might be two situations when we examine high key. If
2271 : : * current child page is referenced by given target downlink, we
2272 : : * should look to the next offset number for matching key from
2273 : : * target page.
2274 : : *
2275 : : * Alternatively, we're following rightlinks somewhere in the
2276 : : * middle between page referenced by previous target's downlink
2277 : : * and the page referenced by current target's downlink. If
2278 : : * current child page hasn't incomplete split flag set, then its
2279 : : * high key should match to the target's key of current offset
2280 : : * number. This happens when a previous call here (to
2281 : : * bt_child_highkey_check()) found an incomplete split, and we
2282 : : * reach a right sibling page without a downlink -- the right
2283 : : * sibling page's high key still needs to be matched to a
2284 : : * separator key on the parent/target level.
2285 : : *
2286 : : * Don't apply OffsetNumberNext() to target_downlinkoffnum when we
2287 : : * already had to step right on the child level. Our traversal of
2288 : : * the child level must try to move in perfect lockstep behind (to
2289 : : * the left of) the target/parent level traversal.
2290 : : */
2291 [ + - ]: 3453 : if (blkno == downlink)
2292 : 3453 : pivotkey_offset = OffsetNumberNext(target_downlinkoffnum);
2293 : : else
2195 akorotkov@postgresql 2294 :UBC 0 : pivotkey_offset = target_downlinkoffnum;
2295 : :
1444 michael@paquier.xyz 2296 :CBC 3453 : topaque = BTPageGetOpaque(state->target);
2297 : :
2195 akorotkov@postgresql 2298 [ + - ]: 3453 : if (!offset_is_negative_infinity(topaque, pivotkey_offset))
2299 : : {
2300 : : /*
2301 : : * If we're looking for the next pivot tuple in target page,
2302 : : * but there is no more pivot tuples, then we should match to
2303 : : * high key instead.
2304 : : */
2305 [ + + ]: 3453 : if (pivotkey_offset > PageGetMaxOffsetNumber(state->target))
2306 : : {
2307 [ - + ]: 5 : if (P_RIGHTMOST(topaque))
2195 akorotkov@postgresql 2308 [ # # ]:UBC 0 : ereport(ERROR,
2309 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2310 : : errmsg("child high key is greater than rightmost pivot key on target level in index \"%s\"",
2311 : : RelationGetRelationName(state->rel)),
2312 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%08X.",
2313 : : state->targetblock, blkno,
2314 : : LSN_FORMAT_ARGS(state->targetlsn))));
2195 akorotkov@postgresql 2315 :CBC 5 : pivotkey_offset = P_HIKEY;
2316 : : }
2317 : 3453 : itemid = PageGetItemIdCareful(state, state->targetblock,
2318 : : state->target, pivotkey_offset);
2319 : 3453 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2320 : : }
2321 : : else
2322 : : {
2323 : : /*
2324 : : * We cannot try to match child's high key to a negative
2325 : : * infinity key in target, since there is nothing to compare.
2326 : : * However, it's still possible to match child's high key
2327 : : * outside of target page. The reason why we're are is that
2328 : : * bt_child_highkey_check() was previously called for the
2329 : : * cousin page of 'loaded_child', which is incomplete split.
2330 : : * So, now we traverse to the right of that cousin page and
2331 : : * current child level page under consideration still belongs
2332 : : * to the subtree of target's left sibling. Thus, we need to
2333 : : * match child's high key to its left uncle page high key.
2334 : : * Thankfully we saved it, it's called a "low key" of target
2335 : : * page.
2336 : : */
2195 akorotkov@postgresql 2337 [ # # ]:UBC 0 : if (!state->lowkey)
2338 [ # # ]: 0 : ereport(ERROR,
2339 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2340 : : errmsg("can't find left sibling high key in index \"%s\"",
2341 : : RelationGetRelationName(state->rel)),
2342 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%08X.",
2343 : : state->targetblock, blkno,
2344 : : LSN_FORMAT_ARGS(state->targetlsn))));
2345 : 0 : itup = state->lowkey;
2346 : : }
2347 : :
2006 pg@bowt.ie 2348 [ - + ]:CBC 3453 : if (!bt_pivot_tuple_identical(state->heapkeyspace, highkey, itup))
2349 : : {
2195 akorotkov@postgresql 2350 [ # # ]:UBC 0 : ereport(ERROR,
2351 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2352 : : errmsg("mismatch between parent key and child high key in index \"%s\"",
2353 : : RelationGetRelationName(state->rel)),
2354 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%08X.",
2355 : : state->targetblock, blkno,
2356 : : LSN_FORMAT_ARGS(state->targetlsn))));
2357 : : }
2358 : : }
2359 : :
2360 : : /* Exit if we already found next downlink */
2195 akorotkov@postgresql 2361 [ + + ]:CBC 3476 : if (blkno == downlink)
2362 : : {
2363 : 3474 : state->prevrightlink = opaque->btpo_next;
2364 : 3474 : state->previncompletesplit = rightsplit;
2365 : 3474 : return;
2366 : : }
2367 : :
2368 : : /* Traverse to the next page using rightlink */
2195 akorotkov@postgresql 2369 :GBC 2 : blkno = opaque->btpo_next;
2370 : :
2371 : : /* Free page contents if it's allocated by us */
2372 [ + - ]: 2 : if (page != loaded_child)
2373 : 2 : pfree(page);
2374 : 2 : first = false;
2375 : : }
2376 : : }
2377 : :
2378 : : /*
2379 : : * Checks one of target's downlink against its child page.
2380 : : *
2381 : : * Conceptually, the target page continues to be what is checked here. The
2382 : : * target block is still blamed in the event of finding an invariant violation.
2383 : : * The downlink insertion into the target is probably where any problem raised
2384 : : * here arises, and there is no such thing as a parent link, so doing the
2385 : : * verification this way around is much more practical.
2386 : : *
2387 : : * This function visits child page and it's sequentially called for each
2388 : : * downlink of target page. Assuming this we also check downlink connectivity
2389 : : * here in order to save child page visits.
2390 : : */
2391 : : static void
2195 akorotkov@postgresql 2392 :CBC 3448 : bt_child_check(BtreeCheckState *state, BTScanInsert targetkey,
2393 : : OffsetNumber downlinkoffnum)
2394 : : {
2395 : : ItemId itemid;
2396 : : IndexTuple itup;
2397 : : BlockNumber childblock;
2398 : : OffsetNumber offset;
2399 : : OffsetNumber maxoffset;
2400 : : Page child;
2401 : : BTPageOpaque copaque;
2402 : : BTPageOpaque topaque;
2403 : :
2404 : 3448 : itemid = PageGetItemIdCareful(state, state->targetblock,
2405 : : state->target, downlinkoffnum);
2406 : 3448 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2407 : 3448 : childblock = BTreeTupleGetDownLink(itup);
2408 : :
2409 : : /*
2410 : : * Caller must have ShareLock on target relation, because of
2411 : : * considerations around page deletion by VACUUM.
2412 : : *
2413 : : * NB: In general, page deletion deletes the right sibling's downlink, not
2414 : : * the downlink of the page being deleted; the deleted page's downlink is
2415 : : * reused for its sibling. The key space is thereby consolidated between
2416 : : * the deleted page and its right sibling. (We cannot delete a parent
2417 : : * page's rightmost child unless it is the last child page, and we intend
2418 : : * to also delete the parent itself.)
2419 : : *
2420 : : * If this verification happened without a ShareLock, the following race
2421 : : * condition could cause false positives:
2422 : : *
2423 : : * In general, concurrent page deletion might occur, including deletion of
2424 : : * the left sibling of the child page that is examined here. If such a
2425 : : * page deletion were to occur, closely followed by an insertion into the
2426 : : * newly expanded key space of the child, a window for the false positive
2427 : : * opens up: the stale parent/target downlink originally followed to get
2428 : : * to the child legitimately ceases to be a lower bound on all items in
2429 : : * the page, since the key space was concurrently expanded "left".
2430 : : * (Insertion followed the "new" downlink for the child, not our now-stale
2431 : : * downlink, which was concurrently physically removed in target/parent as
2432 : : * part of deletion's first phase.)
2433 : : *
2434 : : * While we use various techniques elsewhere to perform cross-page
2435 : : * verification for !readonly callers, a similar trick seems difficult
2436 : : * here. The tricks used by bt_recheck_sibling_links and by
2437 : : * bt_right_page_check_scankey both involve verification of a same-level,
2438 : : * cross-sibling invariant. Cross-level invariants are far more squishy,
2439 : : * though. The nbtree REDO routines do not actually couple buffer locks
2440 : : * across levels during page splits, so making any cross-level check work
2441 : : * reliably in !readonly mode may be impossible.
2442 : : */
3293 andres@anarazel.de 2443 [ - + ]: 3448 : Assert(state->readonly);
2444 : :
2445 : : /*
2446 : : * Verify child page has the downlink key from target page (its parent) as
2447 : : * a lower bound; downlink must be strictly less than all keys on the
2448 : : * page.
2449 : : *
2450 : : * Check all items, rather than checking just the first and trusting that
2451 : : * the operator class obeys the transitive law.
2452 : : */
1444 michael@paquier.xyz 2453 : 3448 : topaque = BTPageGetOpaque(state->target);
3293 andres@anarazel.de 2454 : 3448 : child = palloc_btree_page(state, childblock);
1444 michael@paquier.xyz 2455 : 3448 : copaque = BTPageGetOpaque(child);
3293 andres@anarazel.de 2456 : 3448 : maxoffset = PageGetMaxOffsetNumber(child);
2457 : :
2458 : : /*
2459 : : * Since we've already loaded the child block, combine this check with
2460 : : * check for downlink connectivity.
2461 : : */
2195 akorotkov@postgresql 2462 : 3448 : bt_child_highkey_check(state, downlinkoffnum,
2463 : : child, topaque->btpo_level);
2464 : :
2465 : : /*
2466 : : * Since there cannot be a concurrent VACUUM operation in readonly mode,
2467 : : * and since a page has no links within other pages (siblings and parent)
2468 : : * once it is marked fully deleted, it should be impossible to land on a
2469 : : * fully deleted page.
2470 : : *
2471 : : * It does not quite make sense to enforce that the page cannot even be
2472 : : * half-dead, despite the fact the downlink is modified at the same stage
2473 : : * that the child leaf page is marked half-dead. That's incorrect because
2474 : : * there may occasionally be multiple downlinks from a chain of pages
2475 : : * undergoing deletion, where multiple successive calls are made to
2476 : : * _bt_unlink_halfdead_page() by VACUUM before it can finally safely mark
2477 : : * the leaf page as fully dead. While _bt_mark_page_halfdead() usually
2478 : : * removes the downlink to the leaf page that is marked half-dead, that's
2479 : : * not guaranteed, so it's possible we'll land on a half-dead page with a
2480 : : * downlink due to an interrupted multi-level page deletion.
2481 : : *
2482 : : * We go ahead with our checks if the child page is half-dead. It's safe
2483 : : * to do so because we do not test the child's high key, so it does not
2484 : : * matter that the original high key will have been replaced by a dummy
2485 : : * truncated high key within _bt_mark_page_halfdead(). All other page
2486 : : * items are left intact on a half-dead page, so there is still something
2487 : : * to test.
2488 : : */
2881 teodor@sigaev.ru 2489 [ - + ]: 3448 : if (P_ISDELETED(copaque))
2881 teodor@sigaev.ru 2490 [ # # ]:UBC 0 : ereport(ERROR,
2491 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2492 : : errmsg("downlink to deleted page found in index \"%s\"",
2493 : : RelationGetRelationName(state->rel)),
2494 : : errdetail_internal("Parent block=%u child block=%u parent page lsn=%X/%08X.",
2495 : : state->targetblock, childblock,
2496 : : LSN_FORMAT_ARGS(state->targetlsn))));
2497 : :
3293 andres@anarazel.de 2498 [ + + ]:CBC 3448 : for (offset = P_FIRSTDATAKEY(copaque);
2499 [ + + ]: 1179908 : offset <= maxoffset;
2500 : 1176460 : offset = OffsetNumberNext(offset))
2501 : : {
2502 : : /*
2503 : : * Skip comparison of target page key against "negative infinity"
2504 : : * item, if any. Checking it would indicate that it's not a strict
2505 : : * lower bound, but that's only because of the hard-coding for
2506 : : * negative infinity items within _bt_compare().
2507 : : *
2508 : : * If nbtree didn't truncate negative infinity tuples during internal
2509 : : * page splits then we'd expect child's negative infinity key to be
2510 : : * equal to the scankey/downlink from target/parent (it would be a
2511 : : * "low key" in this hypothetical scenario, and so it would still need
2512 : : * to be treated as a special case here).
2513 : : *
2514 : : * Negative infinity items can be thought of as a strict lower bound
2515 : : * that works transitively, with the last non-negative-infinity pivot
2516 : : * followed during a descent from the root as its "true" strict lower
2517 : : * bound. Only a small number of negative infinity items are truly
2518 : : * negative infinity; those that are the first items of leftmost
2519 : : * internal pages. In more general terms, a negative infinity item is
2520 : : * only negative infinity with respect to the subtree that the page is
2521 : : * at the root of.
2522 : : *
2523 : : * See also: bt_rootdescend(), which can even detect transitive
2524 : : * inconsistencies on cousin leaf pages.
2525 : : */
2526 [ + + ]: 1176460 : if (offset_is_negative_infinity(copaque, offset))
2527 : 4 : continue;
2528 : :
2516 pg@bowt.ie 2529 [ - + ]: 1176456 : if (!invariant_l_nontarget_offset(state, targetkey, childblock, child,
2530 : : offset))
3293 andres@anarazel.de 2531 [ # # ]:UBC 0 : ereport(ERROR,
2532 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2533 : : errmsg("down-link lower bound invariant violated for index \"%s\"",
2534 : : RelationGetRelationName(state->rel)),
2535 : : errdetail_internal("Parent block=%u child index tid=(%u,%u) parent page lsn=%X/%08X.",
2536 : : state->targetblock, childblock, offset,
2537 : : LSN_FORMAT_ARGS(state->targetlsn))));
2538 : : }
2539 : :
3293 andres@anarazel.de 2540 :CBC 3448 : pfree(child);
2541 : 3448 : }
2542 : :
2543 : : /*
2544 : : * Checks if page is missing a downlink that it should have.
2545 : : *
2546 : : * A page that lacks a downlink/parent may indicate corruption. However, we
2547 : : * must account for the fact that a missing downlink can occasionally be
2548 : : * encountered in a non-corrupt index. This can be due to an interrupted page
2549 : : * split, or an interrupted multi-level page deletion (i.e. there was a hard
2550 : : * crash or an error during a page split, or while VACUUM was deleting a
2551 : : * multi-level chain of pages).
2552 : : *
2553 : : * Note that this can only be called in readonly mode, so there is no need to
2554 : : * be concerned about concurrent page splits or page deletions.
2555 : : */
2556 : : static void
2195 akorotkov@postgresql 2557 :GBC 1 : bt_downlink_missing_check(BtreeCheckState *state, bool rightsplit,
2558 : : BlockNumber blkno, Page page)
2559 : : {
1444 michael@paquier.xyz 2560 : 1 : BTPageOpaque opaque = BTPageGetOpaque(page);
2561 : : ItemId itemid;
2562 : : IndexTuple itup;
2563 : : Page child;
2564 : : BTPageOpaque copaque;
2565 : : uint32 level;
2566 : : BlockNumber childblk;
2567 : : XLogRecPtr pagelsn;
2568 : :
2195 akorotkov@postgresql 2569 [ - + ]: 1 : Assert(state->readonly);
2570 [ - + ]: 1 : Assert(!P_IGNORE(opaque));
2571 : :
2572 : : /* No next level up with downlinks to fingerprint from the true root */
2573 [ - + ]: 1 : if (P_ISROOT(opaque))
2881 teodor@sigaev.ru 2574 :UBC 0 : return;
2575 : :
2195 akorotkov@postgresql 2576 :GBC 1 : pagelsn = PageGetLSN(page);
2577 : :
2578 : : /*
2579 : : * Incomplete (interrupted) page splits can account for the lack of a
2580 : : * downlink. Some inserting transaction should eventually complete the
2581 : : * page split in passing, when it notices that the left sibling page is
2582 : : * P_INCOMPLETE_SPLIT().
2583 : : *
2584 : : * In general, VACUUM is not prepared for there to be no downlink to a
2585 : : * page that it deletes. This is the main reason why the lack of a
2586 : : * downlink can be reported as corruption here. It's not obvious that an
2587 : : * invalid missing downlink can result in wrong answers to queries,
2588 : : * though, since index scans that land on the child may end up
2589 : : * consistently moving right. The handling of concurrent page splits (and
2590 : : * page deletions) within _bt_moveright() cannot distinguish
2591 : : * inconsistencies that last for a moment from inconsistencies that are
2592 : : * permanent and irrecoverable.
2593 : : *
2594 : : * VACUUM isn't even prepared to delete pages that have no downlink due to
2595 : : * an incomplete page split, but it can detect and reason about that case
2596 : : * by design, so it shouldn't be taken to indicate corruption. See
2597 : : * _bt_pagedel() for full details.
2598 : : */
2599 [ + - ]: 1 : if (rightsplit)
2600 : : {
2881 teodor@sigaev.ru 2601 [ - + ]: 1 : ereport(DEBUG1,
2602 : : (errcode(ERRCODE_NO_DATA),
2603 : : errmsg_internal("harmless interrupted page split detected in index \"%s\"",
2604 : : RelationGetRelationName(state->rel)),
2605 : : errdetail_internal("Block=%u level=%u left sibling=%u page lsn=%X/%08X.",
2606 : : blkno, opaque->btpo_level,
2607 : : opaque->btpo_prev,
2608 : : LSN_FORMAT_ARGS(pagelsn))));
2609 : 1 : return;
2610 : : }
2611 : :
2612 : : /*
2613 : : * Page under check is probably the "top parent" of a multi-level page
2614 : : * deletion. We'll need to descend the subtree to make sure that
2615 : : * descendant pages are consistent with that, though.
2616 : : *
2617 : : * If the page (which must be non-ignorable) is a leaf page, then clearly
2618 : : * it can't be the top parent. The lack of a downlink is probably a
2619 : : * symptom of a broad problem that could just as easily cause
2620 : : * inconsistencies anywhere else.
2621 : : */
2195 akorotkov@postgresql 2622 [ # # ]:UBC 0 : if (P_ISLEAF(opaque))
2881 teodor@sigaev.ru 2623 [ # # ]: 0 : ereport(ERROR,
2624 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2625 : : errmsg("leaf index block lacks downlink in index \"%s\"",
2626 : : RelationGetRelationName(state->rel)),
2627 : : errdetail_internal("Block=%u page lsn=%X/%08X.",
2628 : : blkno,
2629 : : LSN_FORMAT_ARGS(pagelsn))));
2630 : :
2631 : : /* Descend from the given page, which is an internal page */
2632 [ # # ]: 0 : elog(DEBUG1, "checking for interrupted multi-level deletion due to missing downlink in index \"%s\"",
2633 : : RelationGetRelationName(state->rel));
2634 : :
1845 pg@bowt.ie 2635 : 0 : level = opaque->btpo_level;
2195 akorotkov@postgresql 2636 [ # # ]: 0 : itemid = PageGetItemIdCareful(state, blkno, page, P_FIRSTDATAKEY(opaque));
2637 : 0 : itup = (IndexTuple) PageGetItem(page, itemid);
2281 pg@bowt.ie 2638 : 0 : childblk = BTreeTupleGetDownLink(itup);
2639 : : for (;;)
2640 : : {
2881 teodor@sigaev.ru 2641 [ # # ]: 0 : CHECK_FOR_INTERRUPTS();
2642 : :
2643 : 0 : child = palloc_btree_page(state, childblk);
1444 michael@paquier.xyz 2644 : 0 : copaque = BTPageGetOpaque(child);
2645 : :
2881 teodor@sigaev.ru 2646 [ # # ]: 0 : if (P_ISLEAF(copaque))
2647 : 0 : break;
2648 : :
2649 : : /* Do an extra sanity check in passing on internal pages */
1845 pg@bowt.ie 2650 [ # # ]: 0 : if (copaque->btpo_level != level - 1)
2881 teodor@sigaev.ru 2651 [ # # ]: 0 : ereport(ERROR,
2652 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2653 : : errmsg_internal("downlink points to block in index \"%s\" whose level is not one level down",
2654 : : RelationGetRelationName(state->rel)),
2655 : : errdetail_internal("Top parent/under check block=%u block pointed to=%u expected level=%u level in pointed to block=%u.",
2656 : : blkno, childblk,
2657 : : level - 1, copaque->btpo_level)));
2658 : :
1845 pg@bowt.ie 2659 : 0 : level = copaque->btpo_level;
2516 2660 : 0 : itemid = PageGetItemIdCareful(state, childblk, child,
2661 [ # # ]: 0 : P_FIRSTDATAKEY(copaque));
2881 teodor@sigaev.ru 2662 : 0 : itup = (IndexTuple) PageGetItem(child, itemid);
2281 pg@bowt.ie 2663 : 0 : childblk = BTreeTupleGetDownLink(itup);
2664 : : /* Be slightly more pro-active in freeing this memory, just in case */
2881 teodor@sigaev.ru 2665 : 0 : pfree(child);
2666 : : }
2667 : :
2668 : : /*
2669 : : * Since there cannot be a concurrent VACUUM operation in readonly mode,
2670 : : * and since a page has no links within other pages (siblings and parent)
2671 : : * once it is marked fully deleted, it should be impossible to land on a
2672 : : * fully deleted page. See bt_child_check() for further details.
2673 : : *
2674 : : * The bt_child_check() P_ISDELETED() check is repeated here because
2675 : : * bt_child_check() does not visit pages reachable through negative
2676 : : * infinity items. Besides, bt_child_check() is unwilling to descend
2677 : : * multiple levels. (The similar bt_child_check() P_ISDELETED() check
2678 : : * within bt_check_level_from_leftmost() won't reach the page either,
2679 : : * since the leaf's live siblings should have their sibling links updated
2680 : : * to bypass the deletion target page when it is marked fully dead.)
2681 : : *
2682 : : * If this error is raised, it might be due to a previous multi-level page
2683 : : * deletion that failed to realize that it wasn't yet safe to mark the
2684 : : * leaf page as fully dead. A "dangling downlink" will still remain when
2685 : : * this happens. The fact that the dangling downlink's page (the leaf's
2686 : : * parent/ancestor page) lacked a downlink is incidental.
2687 : : */
2688 [ # # ]: 0 : if (P_ISDELETED(copaque))
2689 [ # # ]: 0 : ereport(ERROR,
2690 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2691 : : errmsg_internal("downlink to deleted leaf page found in index \"%s\"",
2692 : : RelationGetRelationName(state->rel)),
2693 : : errdetail_internal("Top parent/target block=%u leaf block=%u top parent/under check lsn=%X/%08X.",
2694 : : blkno, childblk,
2695 : : LSN_FORMAT_ARGS(pagelsn))));
2696 : :
2697 : : /*
2698 : : * Iff leaf page is half-dead, its high key top parent link should point
2699 : : * to what VACUUM considered to be the top parent page at the instant it
2700 : : * was interrupted. Provided the high key link actually points to the
2701 : : * page under check, the missing downlink we detected is consistent with
2702 : : * there having been an interrupted multi-level page deletion. This means
2703 : : * that the subtree with the page under check at its root (a page deletion
2704 : : * chain) is in a consistent state, enabling VACUUM to resume deleting the
2705 : : * entire chain the next time it encounters the half-dead leaf page.
2706 : : */
2707 [ # # # # ]: 0 : if (P_ISHALFDEAD(copaque) && !P_RIGHTMOST(copaque))
2708 : : {
2516 pg@bowt.ie 2709 : 0 : itemid = PageGetItemIdCareful(state, childblk, child, P_HIKEY);
2881 teodor@sigaev.ru 2710 : 0 : itup = (IndexTuple) PageGetItem(child, itemid);
2195 akorotkov@postgresql 2711 [ # # ]: 0 : if (BTreeTupleGetTopParent(itup) == blkno)
2881 teodor@sigaev.ru 2712 : 0 : return;
2713 : : }
2714 : :
2715 [ # # ]: 0 : ereport(ERROR,
2716 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2717 : : errmsg("internal index block lacks downlink in index \"%s\"",
2718 : : RelationGetRelationName(state->rel)),
2719 : : errdetail_internal("Block=%u level=%u page lsn=%X/%08X.",
2720 : : blkno, opaque->btpo_level,
2721 : : LSN_FORMAT_ARGS(pagelsn))));
2722 : : }
2723 : :
2724 : : /*
2725 : : * Per-tuple callback from table_index_build_scan, used to determine if index has
2726 : : * all the entries that definitely should have been observed in leaf pages of
2727 : : * the target index (that is, all IndexTuples that were fingerprinted by our
2728 : : * Bloom filter). All heapallindexed checks occur here.
2729 : : *
2730 : : * The redundancy between an index and the table it indexes provides a good
2731 : : * opportunity to detect corruption, especially corruption within the table.
2732 : : * The high level principle behind the verification performed here is that any
2733 : : * IndexTuple that should be in an index following a fresh CREATE INDEX (based
2734 : : * on the same index definition) should also have been in the original,
2735 : : * existing index, which should have used exactly the same representation
2736 : : *
2737 : : * Since the overall structure of the index has already been verified, the most
2738 : : * likely explanation for error here is a corrupt heap page (could be logical
2739 : : * or physical corruption). Index corruption may still be detected here,
2740 : : * though. Only readonly callers will have verified that left links and right
2741 : : * links are in agreement, and so it's possible that a leaf page transposition
2742 : : * within index is actually the source of corruption detected here (for
2743 : : * !readonly callers). The checks performed only for readonly callers might
2744 : : * more accurately frame the problem as a cross-page invariant issue (this
2745 : : * could even be due to recovery not replaying all WAL records). The !readonly
2746 : : * ERROR message raised here includes a HINT about retrying with readonly
2747 : : * verification, just in case it's a cross-page invariant issue, though that
2748 : : * isn't particularly likely.
2749 : : *
2750 : : * table_index_build_scan() expects to be able to find the root tuple when a
2751 : : * heap-only tuple (the live tuple at the end of some HOT chain) needs to be
2752 : : * indexed, in order to replace the actual tuple's TID with the root tuple's
2753 : : * TID (which is what we're actually passed back here). The index build heap
2754 : : * scan code will raise an error when a tuple that claims to be the root of the
2755 : : * heap-only tuple's HOT chain cannot be located. This catches cases where the
2756 : : * original root item offset/root tuple for a HOT chain indicates (for whatever
2757 : : * reason) that the entire HOT chain is dead, despite the fact that the latest
2758 : : * heap-only tuple should be indexed. When this happens, sequential scans may
2759 : : * always give correct answers, and all indexes may be considered structurally
2760 : : * consistent (i.e. the nbtree structural checks would not detect corruption).
2761 : : * It may be the case that only index scans give wrong answers, and yet heap or
2762 : : * SLRU corruption is the real culprit. (While it's true that LP_DEAD bit
2763 : : * setting will probably also leave the index in a corrupt state before too
2764 : : * long, the problem is nonetheless that there is heap corruption.)
2765 : : *
2766 : : * Heap-only tuple handling within table_index_build_scan() works in a way that
2767 : : * helps us to detect index tuples that contain the wrong values (values that
2768 : : * don't match the latest tuple in the HOT chain). This can happen when there
2769 : : * is no superseding index tuple due to a faulty assessment of HOT safety,
2770 : : * perhaps during the original CREATE INDEX. Because the latest tuple's
2771 : : * contents are used with the root TID, an error will be raised when a tuple
2772 : : * with the same TID but non-matching attribute values is passed back to us.
2773 : : * Faulty assessment of HOT-safety was behind at least two distinct CREATE
2774 : : * INDEX CONCURRENTLY bugs that made it into stable releases, one of which was
2775 : : * undetected for many years. In short, the same principle that allows a
2776 : : * REINDEX to repair corruption when there was an (undetected) broken HOT chain
2777 : : * also allows us to detect the corruption in many cases.
2778 : : */
2779 : : static void
2319 andres@anarazel.de 2780 :CBC 1093527 : bt_tuple_present_callback(Relation index, ItemPointer tid, Datum *values,
2781 : : bool *isnull, bool tupleIsAlive, void *checkstate)
2782 : : {
2906 2783 : 1093527 : BtreeCheckState *state = (BtreeCheckState *) checkstate;
2784 : : IndexTuple itup,
2785 : : norm;
2786 : :
2787 [ - + ]: 1093527 : Assert(state->heapallindexed);
2788 : :
2789 : : /* Generate a normalized index tuple for fingerprinting */
2790 : 1093527 : itup = index_form_tuple(RelationGetDescr(index), values, isnull);
2319 2791 : 1093527 : itup->t_tid = *tid;
2594 pg@bowt.ie 2792 : 1093527 : norm = bt_normalize_tuple(state, itup);
2793 : :
2794 : : /* Probe Bloom filter -- tuple should be present */
2795 [ - + ]: 1093527 : if (bloom_lacks_element(state->filter, (unsigned char *) norm,
2796 : : IndexTupleSize(norm)))
2906 andres@anarazel.de 2797 [ # # # # ]:UBC 0 : ereport(ERROR,
2798 : : (errcode(ERRCODE_DATA_CORRUPTED),
2799 : : errmsg("heap tuple (%u,%u) from table \"%s\" lacks matching index tuple within index \"%s\"",
2800 : : ItemPointerGetBlockNumber(&(itup->t_tid)),
2801 : : ItemPointerGetOffsetNumber(&(itup->t_tid)),
2802 : : RelationGetRelationName(state->heaprel),
2803 : : RelationGetRelationName(state->rel)),
2804 : : !state->readonly
2805 : : ? errhint("Retrying verification using the function bt_index_parent_check() might provide a more specific error.")
2806 : : : 0));
2807 : :
2906 andres@anarazel.de 2808 :CBC 1093527 : state->heaptuplespresent++;
2809 : 1093527 : pfree(itup);
2810 : : /* Cannot leak memory here */
2594 pg@bowt.ie 2811 [ + + ]: 1093527 : if (norm != itup)
2812 : 5 : pfree(norm);
2813 : 1093527 : }
2814 : :
2815 : : /*
2816 : : * Normalize an index tuple for fingerprinting.
2817 : : *
2818 : : * In general, index tuple formation is assumed to be deterministic by
2819 : : * heapallindexed verification, and IndexTuples are assumed immutable. While
2820 : : * the LP_DEAD bit is mutable in leaf pages, that's ItemId metadata, which is
2821 : : * not fingerprinted. Normalization is required to compensate for corner
2822 : : * cases where the determinism assumption doesn't quite work.
2823 : : *
2824 : : * There is currently one such case: index_form_tuple() does not try to hide
2825 : : * the source TOAST state of input datums. The executor applies TOAST
2826 : : * compression for heap tuples based on different criteria to the compression
2827 : : * applied within btinsert()'s call to index_form_tuple(): it sometimes
2828 : : * compresses more aggressively, resulting in compressed heap tuple datums but
2829 : : * uncompressed corresponding index tuple datums. A subsequent heapallindexed
2830 : : * verification will get a logically equivalent though bitwise unequal tuple
2831 : : * from index_form_tuple(). False positive heapallindexed corruption reports
2832 : : * could occur without normalizing away the inconsistency.
2833 : : *
2834 : : * Returned tuple is often caller's own original tuple. Otherwise, it is a
2835 : : * new representation of caller's original index tuple, palloc()'d in caller's
2836 : : * memory context.
2837 : : *
2838 : : * Note: This routine is not concerned with distinctions about the
2839 : : * representation of tuples beyond those that might break heapallindexed
2840 : : * verification. In particular, it won't try to normalize opclass-equal
2841 : : * datums with potentially distinct representations (e.g., btree/numeric_ops
2842 : : * index datums will not get their display scale normalized-away here).
2843 : : * Caller does normalization for non-pivot tuples that have a posting list,
2844 : : * since dummy CREATE INDEX callback code generates new tuples with the same
2845 : : * normalized representation.
2846 : : */
2847 : : static IndexTuple
2848 : 2208842 : bt_normalize_tuple(BtreeCheckState *state, IndexTuple itup)
2849 : : {
2850 : 2208842 : TupleDesc tupleDescriptor = RelationGetDescr(state->rel);
2851 : : Datum normalized[INDEX_MAX_KEYS];
2852 : : bool isnull[INDEX_MAX_KEYS];
2853 : : bool need_free[INDEX_MAX_KEYS];
2854 : 2208842 : bool formnewtup = false;
2855 : : IndexTuple reformed;
2856 : : int i;
2857 : :
2858 : : /* Caller should only pass "logical" non-pivot tuples here */
2209 2859 [ + - - + ]: 2208842 : Assert(!BTreeTupleIsPosting(itup) && !BTreeTupleIsPivot(itup));
2860 : :
2861 : : /* Easy case: It's immediately clear that tuple has no varlena datums */
2594 2862 [ + + ]: 2208842 : if (!IndexTupleHasVarwidths(itup))
2863 : 2208818 : return itup;
2864 : :
2865 [ + + ]: 48 : for (i = 0; i < tupleDescriptor->natts; i++)
2866 : : {
2867 : : Form_pg_attribute att;
2868 : :
2869 : 24 : att = TupleDescAttr(tupleDescriptor, i);
2870 : :
2871 : : /* Assume untoasted/already normalized datum initially */
722 akorotkov@postgresql 2872 : 24 : need_free[i] = false;
2594 pg@bowt.ie 2873 : 24 : normalized[i] = index_getattr(itup, att->attnum,
2874 : : tupleDescriptor,
2875 : : &isnull[i]);
2876 [ + - + - : 24 : if (att->attbyval || att->attlen != -1 || isnull[i])
- + ]
2594 pg@bowt.ie 2877 :UBC 0 : continue;
2878 : :
2879 : : /*
2880 : : * Callers always pass a tuple that could safely be inserted into the
2881 : : * index without further processing, so an external varlena header
2882 : : * should never be encountered here
2883 : : */
2594 pg@bowt.ie 2884 [ - + ]:CBC 24 : if (VARATT_IS_EXTERNAL(DatumGetPointer(normalized[i])))
2594 pg@bowt.ie 2885 [ # # ]:UBC 0 : ereport(ERROR,
2886 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2887 : : errmsg("external varlena datum in tuple that references heap row (%u,%u) in index \"%s\"",
2888 : : ItemPointerGetBlockNumber(&(itup->t_tid)),
2889 : : ItemPointerGetOffsetNumber(&(itup->t_tid)),
2890 : : RelationGetRelationName(state->rel))));
722 akorotkov@postgresql 2891 [ + + + + ]:CBC 46 : else if (!VARATT_IS_COMPRESSED(DatumGetPointer(normalized[i])) &&
2892 [ + + ]: 22 : VARSIZE(DatumGetPointer(normalized[i])) > TOAST_INDEX_TARGET &&
2893 [ + + ]: 21 : (att->attstorage == TYPSTORAGE_EXTENDED ||
2894 [ - + ]: 16 : att->attstorage == TYPSTORAGE_MAIN))
2895 : : {
2896 : : /*
2897 : : * This value will be compressed by index_form_tuple() with the
2898 : : * current storage settings. We may be here because this tuple
2899 : : * was formed with different storage settings. So, force forming.
2900 : : */
2901 : 5 : formnewtup = true;
2902 : : }
2594 pg@bowt.ie 2903 [ + + ]: 19 : else if (VARATT_IS_COMPRESSED(DatumGetPointer(normalized[i])))
2904 : : {
2905 : 2 : formnewtup = true;
2906 : 2 : normalized[i] = PointerGetDatum(PG_DETOAST_DATUM(normalized[i]));
722 akorotkov@postgresql 2907 : 2 : need_free[i] = true;
2908 : : }
2909 : :
2910 : : /*
2911 : : * Short tuples may have 1B or 4B header. Convert 4B header of short
2912 : : * tuples to 1B
2913 : : */
2914 [ + + + + ]: 17 : else if (VARATT_CAN_MAKE_SHORT(DatumGetPointer(normalized[i])))
2915 : : {
2916 : : /* convert to short varlena */
2917 : 1 : Size len = VARATT_CONVERTED_SHORT_SIZE(DatumGetPointer(normalized[i]));
2918 : 1 : char *data = palloc(len);
2919 : :
2920 : 1 : SET_VARSIZE_SHORT(data, len);
2921 : 1 : memcpy(data + 1, VARDATA(DatumGetPointer(normalized[i])), len - 1);
2922 : :
2923 : 1 : formnewtup = true;
2924 : 1 : normalized[i] = PointerGetDatum(data);
2925 : 1 : need_free[i] = true;
2926 : : }
2927 : : }
2928 : :
2929 : : /*
2930 : : * Easier case: Tuple has varlena datums, none of which are compressed or
2931 : : * short with 4B header
2932 : : */
2594 pg@bowt.ie 2933 [ + + ]: 24 : if (!formnewtup)
2934 : 16 : return itup;
2935 : :
2936 : : /*
2937 : : * Hard case: Tuple had compressed varlena datums that necessitate
2938 : : * creating normalized version of the tuple from uncompressed input datums
2939 : : * (normalized input datums). This is rather naive, but shouldn't be
2940 : : * necessary too often.
2941 : : *
2942 : : * In the heap, tuples may contain short varlena datums with both 1B
2943 : : * header and 4B headers. But the corresponding index tuple should always
2944 : : * have such varlena's with 1B headers. So, if there is a short varlena
2945 : : * with 4B header, we need to convert it for fingerprinting.
2946 : : *
2947 : : * Note that we rely on deterministic index_form_tuple() TOAST compression
2948 : : * of normalized input.
2949 : : */
2950 : 8 : reformed = index_form_tuple(tupleDescriptor, normalized, isnull);
2951 : 8 : reformed->t_tid = itup->t_tid;
2952 : :
2953 : : /* Cannot leak memory here */
2954 [ + + ]: 16 : for (i = 0; i < tupleDescriptor->natts; i++)
722 akorotkov@postgresql 2955 [ + + ]: 8 : if (need_free[i])
2594 pg@bowt.ie 2956 : 3 : pfree(DatumGetPointer(normalized[i]));
2957 : :
2958 : 8 : return reformed;
2959 : : }
2960 : :
2961 : : /*
2962 : : * Produce palloc()'d "plain" tuple for nth posting list entry/TID.
2963 : : *
2964 : : * In general, deduplication is not supposed to change the logical contents of
2965 : : * an index. Multiple index tuples are merged together into one equivalent
2966 : : * posting list index tuple when convenient.
2967 : : *
2968 : : * heapallindexed verification must normalize-away this variation in
2969 : : * representation by converting posting list tuples into two or more "plain"
2970 : : * tuples. Each tuple must be fingerprinted separately -- there must be one
2971 : : * tuple for each corresponding Bloom filter probe during the heap scan.
2972 : : *
2973 : : * Note: Caller still needs to call bt_normalize_tuple() with returned tuple.
2974 : : */
2975 : : static inline IndexTuple
2209 2976 : 27116 : bt_posting_plain_tuple(IndexTuple itup, int n)
2977 : : {
2978 [ - + ]: 27116 : Assert(BTreeTupleIsPosting(itup));
2979 : :
2980 : : /* Returns non-posting-list tuple */
2981 : 27116 : return _bt_form_posting(itup, BTreeTupleGetPostingN(itup, n), 1);
2982 : : }
2983 : :
2984 : : /*
2985 : : * Search for itup in index, starting from fast root page. itup must be a
2986 : : * non-pivot tuple. This is only supported with heapkeyspace indexes, since
2987 : : * we rely on having fully unique keys to find a match with only a single
2988 : : * visit to a leaf page, barring an interrupted page split, where we may have
2989 : : * to move right. (A concurrent page split is impossible because caller must
2990 : : * be readonly caller.)
2991 : : *
2992 : : * This routine can detect very subtle transitive consistency issues across
2993 : : * more than one level of the tree. Leaf pages all have a high key (even the
2994 : : * rightmost page has a conceptual positive infinity high key), but not a low
2995 : : * key. Their downlink in parent is a lower bound, which along with the high
2996 : : * key is almost enough to detect every possible inconsistency. A downlink
2997 : : * separator key value won't always be available from parent, though, because
2998 : : * the first items of internal pages are negative infinity items, truncated
2999 : : * down to zero attributes during internal page splits. While it's true that
3000 : : * bt_child_check() and the high key check can detect most imaginable key
3001 : : * space problems, there are remaining problems it won't detect with non-pivot
3002 : : * tuples in cousin leaf pages. Starting a search from the root for every
3003 : : * existing leaf tuple detects small inconsistencies in upper levels of the
3004 : : * tree that cannot be detected any other way. (Besides all this, this is
3005 : : * probably also useful as a direct test of the code used by index scans
3006 : : * themselves.)
3007 : : */
3008 : : static bool
2552 3009 : 782487 : bt_rootdescend(BtreeCheckState *state, IndexTuple itup)
3010 : : {
3011 : : BTScanInsert key;
3012 : : Buffer lbuf;
3013 : : bool exists;
3014 : :
1009 3015 : 782487 : key = _bt_mkscankey(state->rel, itup);
2552 3016 [ + - - + ]: 782487 : Assert(key->heapkeyspace && key->scantid != NULL);
3017 : :
3018 : : /*
3019 : : * Search from root.
3020 : : *
3021 : : * Ideally, we would arrange to only move right within _bt_search() when
3022 : : * an interrupted page split is detected (i.e. when the incomplete split
3023 : : * bit is found to be set), but for now we accept the possibility that
3024 : : * that could conceal an inconsistency.
3025 : : */
3026 [ + - - + ]: 782487 : Assert(state->readonly && state->rootdescend);
3027 : 782487 : exists = false;
3 pg@bowt.ie 3028 :GNC 782487 : _bt_search(state->rel, NULL, key, &lbuf, BT_READ, false);
3029 : :
2552 pg@bowt.ie 3030 [ + - ]:CBC 782487 : if (BufferIsValid(lbuf))
3031 : : {
3032 : : BTInsertStateData insertstate;
3033 : : OffsetNumber offnum;
3034 : : Page page;
3035 : :
3036 : 782487 : insertstate.itup = itup;
3037 : 782487 : insertstate.itemsz = MAXALIGN(IndexTupleSize(itup));
3038 : 782487 : insertstate.itup_key = key;
2209 3039 : 782487 : insertstate.postingoff = 0;
2552 3040 : 782487 : insertstate.bounds_valid = false;
3041 : 782487 : insertstate.buf = lbuf;
3042 : :
3043 : : /* Get matching tuple on leaf page */
3044 : 782487 : offnum = _bt_binsrch_insert(state->rel, &insertstate);
3045 : : /* Compare first >= matching item on leaf page, if any */
3046 : 782487 : page = BufferGetPage(lbuf);
3047 : : /* Should match on first heap TID when tuple has a posting list */
3048 [ + - ]: 782487 : if (offnum <= PageGetMaxOffsetNumber(page) &&
2209 3049 [ + - + - ]: 1564974 : insertstate.postingoff <= 0 &&
2552 3050 : 782487 : _bt_compare(state->rel, key, page, offnum) == 0)
3051 : 782487 : exists = true;
3052 : 782487 : _bt_relbuf(state->rel, lbuf);
3053 : : }
3054 : :
3055 : 782487 : pfree(key);
3056 : :
3057 : 782487 : return exists;
3058 : : }
3059 : :
3060 : : /*
3061 : : * Is particular offset within page (whose special state is passed by caller)
3062 : : * the page negative-infinity item?
3063 : : *
3064 : : * As noted in comments above _bt_compare(), there is special handling of the
3065 : : * first data item as a "negative infinity" item. The hard-coding within
3066 : : * _bt_compare() makes comparing this item for the purposes of verification
3067 : : * pointless at best, since the IndexTuple only contains a valid TID (a
3068 : : * reference TID to child page).
3069 : : */
3070 : : static inline bool
3293 andres@anarazel.de 3071 : 3823555 : offset_is_negative_infinity(BTPageOpaque opaque, OffsetNumber offset)
3072 : : {
3073 : : /*
3074 : : * For internal pages only, the first item after high key, if any, is
3075 : : * negative infinity item. Internal pages always have a negative infinity
3076 : : * item, whereas leaf pages never have one. This implies that negative
3077 : : * infinity item is either first or second line item, or there is none
3078 : : * within page.
3079 : : *
3080 : : * Negative infinity items are a special case among pivot tuples. They
3081 : : * always have zero attributes, while all other pivot tuples always have
3082 : : * nkeyatts attributes.
3083 : : *
3084 : : * Right-most pages don't have a high key, but could be said to
3085 : : * conceptually have a "positive infinity" high key. Thus, there is a
3086 : : * symmetry between down link items in parent pages, and high keys in
3087 : : * children. Together, they represent the part of the key space that
3088 : : * belongs to each page in the index. For example, all children of the
3089 : : * root page will have negative infinity as a lower bound from root
3090 : : * negative infinity downlink, and positive infinity as an upper bound
3091 : : * (implicitly, from "imaginary" positive infinity high key in root).
3092 : : */
3093 [ + + + + : 3823555 : return !P_ISLEAF(opaque) && offset == P_FIRSTDATAKEY(opaque);
+ + ]
3094 : : }
3095 : :
3096 : : /*
3097 : : * Does the invariant hold that the key is strictly less than a given upper
3098 : : * bound offset item?
3099 : : *
3100 : : * Verifies line pointer on behalf of caller.
3101 : : *
3102 : : * If this function returns false, convention is that caller throws error due
3103 : : * to corruption.
3104 : : */
3105 : : static inline bool
2552 pg@bowt.ie 3106 : 2633854 : invariant_l_offset(BtreeCheckState *state, BTScanInsert key,
3107 : : OffsetNumber upperbound)
3108 : : {
3109 : : ItemId itemid;
3110 : : int32 cmp;
3111 : :
828 3112 [ + - - + ]: 2633854 : Assert(!key->nextkey && key->backward);
3113 : :
3114 : : /* Verify line pointer before checking tuple */
2516 3115 : 2633854 : itemid = PageGetItemIdCareful(state, state->targetblock, state->target,
3116 : : upperbound);
3117 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
2552 3118 [ - + ]: 2633854 : if (!key->heapkeyspace)
2552 pg@bowt.ie 3119 :UBC 0 : return invariant_leq_offset(state, key, upperbound);
3120 : :
2552 pg@bowt.ie 3121 :CBC 2633854 : cmp = _bt_compare(state->rel, key, state->target, upperbound);
3122 : :
3123 : : /*
3124 : : * _bt_compare() is capable of determining that a scankey with a
3125 : : * filled-out attribute is greater than pivot tuples where the comparison
3126 : : * is resolved at a truncated attribute (value of attribute in pivot is
3127 : : * minus infinity). However, it is not capable of determining that a
3128 : : * scankey is _less than_ a tuple on the basis of a comparison resolved at
3129 : : * _scankey_ minus infinity attribute. Complete an extra step to simulate
3130 : : * having minus infinity values for omitted scankey attribute(s).
3131 : : */
3132 [ - + ]: 2633854 : if (cmp == 0)
3133 : : {
3134 : : BTPageOpaque topaque;
3135 : : IndexTuple ritup;
3136 : : int uppnkeyatts;
3137 : : ItemPointer rheaptid;
3138 : : bool nonpivot;
3139 : :
2552 pg@bowt.ie 3140 :UBC 0 : ritup = (IndexTuple) PageGetItem(state->target, itemid);
1444 michael@paquier.xyz 3141 : 0 : topaque = BTPageGetOpaque(state->target);
2552 pg@bowt.ie 3142 [ # # # # : 0 : nonpivot = P_ISLEAF(topaque) && upperbound >= P_FIRSTDATAKEY(topaque);
# # ]
3143 : :
3144 : : /* Get number of keys + heap TID for item to the right */
3145 [ # # # # : 0 : uppnkeyatts = BTreeTupleGetNKeyAtts(ritup, state->rel);
# # ]
3146 : 0 : rheaptid = BTreeTupleGetHeapTIDCareful(state, ritup, nonpivot);
3147 : :
3148 : : /* Heap TID is tiebreaker key attribute */
3149 [ # # ]: 0 : if (key->keysz == uppnkeyatts)
3150 [ # # # # ]: 0 : return key->scantid == NULL && rheaptid != NULL;
3151 : :
3152 : 0 : return key->keysz < uppnkeyatts;
3153 : : }
3154 : :
2552 pg@bowt.ie 3155 :CBC 2633854 : return cmp < 0;
3156 : : }
3157 : :
3158 : : /*
3159 : : * Does the invariant hold that the key is less than or equal to a given upper
3160 : : * bound offset item?
3161 : : *
3162 : : * Caller should have verified that upperbound's line pointer is consistent
3163 : : * using PageGetItemIdCareful() call.
3164 : : *
3165 : : * If this function returns false, convention is that caller throws error due
3166 : : * to corruption.
3167 : : */
3168 : : static inline bool
3169 : 2467555 : invariant_leq_offset(BtreeCheckState *state, BTScanInsert key,
3170 : : OffsetNumber upperbound)
3171 : : {
3172 : : int32 cmp;
3173 : :
828 3174 [ + - - + ]: 2467555 : Assert(!key->nextkey && key->backward);
3175 : :
2552 3176 : 2467555 : cmp = _bt_compare(state->rel, key, state->target, upperbound);
3177 : :
3293 andres@anarazel.de 3178 : 2467555 : return cmp <= 0;
3179 : : }
3180 : :
3181 : : /*
3182 : : * Does the invariant hold that the key is strictly greater than a given lower
3183 : : * bound offset item?
3184 : : *
3185 : : * Caller should have verified that lowerbound's line pointer is consistent
3186 : : * using PageGetItemIdCareful() call.
3187 : : *
3188 : : * If this function returns false, convention is that caller throws error due
3189 : : * to corruption.
3190 : : */
3191 : : static inline bool
2552 pg@bowt.ie 3192 : 8398 : invariant_g_offset(BtreeCheckState *state, BTScanInsert key,
3193 : : OffsetNumber lowerbound)
3194 : : {
3195 : : int32 cmp;
3196 : :
828 3197 [ + - - + ]: 8398 : Assert(!key->nextkey && key->backward);
3198 : :
2552 3199 : 8398 : cmp = _bt_compare(state->rel, key, state->target, lowerbound);
3200 : :
3201 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
3202 [ - + ]: 8398 : if (!key->heapkeyspace)
2552 pg@bowt.ie 3203 :UBC 0 : return cmp >= 0;
3204 : :
3205 : : /*
3206 : : * No need to consider the possibility that scankey has attributes that we
3207 : : * need to force to be interpreted as negative infinity. _bt_compare() is
3208 : : * able to determine that scankey is greater than negative infinity. The
3209 : : * distinction between "==" and "<" isn't interesting here, since
3210 : : * corruption is indicated either way.
3211 : : */
2552 pg@bowt.ie 3212 :CBC 8398 : return cmp > 0;
3213 : : }
3214 : :
3215 : : /*
3216 : : * Does the invariant hold that the key is strictly less than a given upper
3217 : : * bound offset item, with the offset relating to a caller-supplied page that
3218 : : * is not the current target page?
3219 : : *
3220 : : * Caller's non-target page is a child page of the target, checked as part of
3221 : : * checking a property of the target page (i.e. the key comes from the
3222 : : * target). Verifies line pointer on behalf of caller.
3223 : : *
3224 : : * If this function returns false, convention is that caller throws error due
3225 : : * to corruption.
3226 : : */
3227 : : static inline bool
3228 : 1176456 : invariant_l_nontarget_offset(BtreeCheckState *state, BTScanInsert key,
3229 : : BlockNumber nontargetblock, Page nontarget,
3230 : : OffsetNumber upperbound)
3231 : : {
3232 : : ItemId itemid;
3233 : : int32 cmp;
3234 : :
828 3235 [ + - - + ]: 1176456 : Assert(!key->nextkey && key->backward);
3236 : :
3237 : : /* Verify line pointer before checking tuple */
2516 3238 : 1176456 : itemid = PageGetItemIdCareful(state, nontargetblock, nontarget,
3239 : : upperbound);
2552 3240 : 1176456 : cmp = _bt_compare(state->rel, key, nontarget, upperbound);
3241 : :
3242 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
3243 [ - + ]: 1176456 : if (!key->heapkeyspace)
2552 pg@bowt.ie 3244 :UBC 0 : return cmp <= 0;
3245 : :
3246 : : /* See invariant_l_offset() for an explanation of this extra step */
2552 pg@bowt.ie 3247 [ + + ]:CBC 1176456 : if (cmp == 0)
3248 : : {
3249 : : IndexTuple child;
3250 : : int uppnkeyatts;
3251 : : ItemPointer childheaptid;
3252 : : BTPageOpaque copaque;
3253 : : bool nonpivot;
3254 : :
3255 : 3442 : child = (IndexTuple) PageGetItem(nontarget, itemid);
1444 michael@paquier.xyz 3256 : 3442 : copaque = BTPageGetOpaque(nontarget);
2552 pg@bowt.ie 3257 [ + - + + : 3442 : nonpivot = P_ISLEAF(copaque) && upperbound >= P_FIRSTDATAKEY(copaque);
+ - ]
3258 : :
3259 : : /* Get number of keys + heap TID for child/non-target item */
3260 [ - + + + : 3442 : uppnkeyatts = BTreeTupleGetNKeyAtts(child, state->rel);
- + ]
3261 : 3442 : childheaptid = BTreeTupleGetHeapTIDCareful(state, child, nonpivot);
3262 : :
3263 : : /* Heap TID is tiebreaker key attribute */
3264 [ + - ]: 3442 : if (key->keysz == uppnkeyatts)
3265 [ + - + - ]: 3442 : return key->scantid == NULL && childheaptid != NULL;
3266 : :
2552 pg@bowt.ie 3267 :UBC 0 : return key->keysz < uppnkeyatts;
3268 : : }
3269 : :
2552 pg@bowt.ie 3270 :CBC 1173014 : return cmp < 0;
3271 : : }
3272 : :
3273 : : /*
3274 : : * Given a block number of a B-Tree page, return page in palloc()'d memory.
3275 : : * While at it, perform some basic checks of the page.
3276 : : *
3277 : : * There is never an attempt to get a consistent view of multiple pages using
3278 : : * multiple concurrent buffer locks; in general, we only acquire a single pin
3279 : : * and buffer lock at a time, which is often all that the nbtree code requires.
3280 : : * (Actually, bt_recheck_sibling_links couples buffer locks, which is the only
3281 : : * exception to this general rule.)
3282 : : *
3283 : : * Operating on a copy of the page is useful because it prevents control
3284 : : * getting stuck in an uninterruptible state when an underlying operator class
3285 : : * misbehaves.
3286 : : */
3287 : : static Page
3293 andres@anarazel.de 3288 : 26790 : palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
3289 : : {
3290 : : Buffer buffer;
3291 : : Page page;
3292 : : BTPageOpaque opaque;
3293 : : OffsetNumber maxoffset;
3294 : :
3295 : 26790 : page = palloc(BLCKSZ);
3296 : :
3297 : : /*
3298 : : * We copy the page into local storage to avoid holding pin on the buffer
3299 : : * longer than we must.
3300 : : */
3301 : 26790 : buffer = ReadBufferExtended(state->rel, MAIN_FORKNUM, blocknum, RBM_NORMAL,
3302 : : state->checkstrategy);
3303 : 26778 : LockBuffer(buffer, BT_READ);
3304 : :
3305 : : /*
3306 : : * Perform the same basic sanity checking that nbtree itself performs for
3307 : : * every page:
3308 : : */
3309 : 26778 : _bt_checkpage(state->rel, buffer);
3310 : :
3311 : : /* Only use copy of page in palloc()'d memory */
3312 : 26778 : memcpy(page, BufferGetPage(buffer), BLCKSZ);
3313 : 26778 : UnlockReleaseBuffer(buffer);
3314 : :
1444 michael@paquier.xyz 3315 : 26778 : opaque = BTPageGetOpaque(page);
3316 : :
3100 tgl@sss.pgh.pa.us 3317 [ + + - + ]: 26778 : if (P_ISMETA(opaque) && blocknum != BTREE_METAPAGE)
3293 andres@anarazel.de 3318 [ # # ]:UBC 0 : ereport(ERROR,
3319 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3320 : : errmsg("invalid meta page found at block %u in index \"%s\"",
3321 : : blocknum, RelationGetRelationName(state->rel))));
3322 : :
3323 : : /* Check page from block that ought to be meta page */
3293 andres@anarazel.de 3324 [ + + ]:CBC 26778 : if (blocknum == BTREE_METAPAGE)
3325 : : {
3326 : 3983 : BTMetaPageData *metad = BTPageGetMeta(page);
3327 : :
3100 tgl@sss.pgh.pa.us 3328 [ + - ]: 3983 : if (!P_ISMETA(opaque) ||
3293 andres@anarazel.de 3329 [ - + ]: 3983 : metad->btm_magic != BTREE_MAGIC)
3293 andres@anarazel.de 3330 [ # # ]:UBC 0 : ereport(ERROR,
3331 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3332 : : errmsg("index \"%s\" meta page is corrupt",
3333 : : RelationGetRelationName(state->rel))));
3334 : :
2902 teodor@sigaev.ru 3335 [ + - ]:CBC 3983 : if (metad->btm_version < BTREE_MIN_VERSION ||
3336 [ - + ]: 3983 : metad->btm_version > BTREE_VERSION)
3293 andres@anarazel.de 3337 [ # # ]:UBC 0 : ereport(ERROR,
3338 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3339 : : errmsg("version mismatch in index \"%s\": file version %d, "
3340 : : "current version %d, minimum supported version %d",
3341 : : RelationGetRelationName(state->rel),
3342 : : metad->btm_version, BTREE_VERSION,
3343 : : BTREE_MIN_VERSION)));
3344 : :
3345 : : /* Finished with metapage checks */
2881 teodor@sigaev.ru 3346 :CBC 3983 : return page;
3347 : : }
3348 : :
3349 : : /*
3350 : : * Deleted pages that still use the old 32-bit XID representation have no
3351 : : * sane "level" field because they type pun the field, but all other pages
3352 : : * (including pages deleted on Postgres 14+) have a valid value.
3353 : : */
1845 pg@bowt.ie 3354 [ - + - - ]: 22795 : if (!P_ISDELETED(opaque) || P_HAS_FULLXID(opaque))
3355 : : {
3356 : : /* Okay, no reason not to trust btpo_level field from page */
3357 : :
3358 [ + + - + ]: 22795 : if (P_ISLEAF(opaque) && opaque->btpo_level != 0)
1845 pg@bowt.ie 3359 [ # # ]:UBC 0 : ereport(ERROR,
3360 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3361 : : errmsg_internal("invalid leaf page level %u for block %u in index \"%s\"",
3362 : : opaque->btpo_level, blocknum,
3363 : : RelationGetRelationName(state->rel))));
3364 : :
1845 pg@bowt.ie 3365 [ + + - + ]:CBC 22795 : if (!P_ISLEAF(opaque) && opaque->btpo_level == 0)
1845 pg@bowt.ie 3366 [ # # ]:UBC 0 : ereport(ERROR,
3367 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3368 : : errmsg_internal("invalid internal page level 0 for block %u in index \"%s\"",
3369 : : blocknum,
3370 : : RelationGetRelationName(state->rel))));
3371 : : }
3372 : :
3373 : : /*
3374 : : * Sanity checks for number of items on page.
3375 : : *
3376 : : * As noted at the beginning of _bt_binsrch(), an internal page must have
3377 : : * children, since there must always be a negative infinity downlink
3378 : : * (there may also be a highkey). In the case of non-rightmost leaf
3379 : : * pages, there must be at least a highkey. The exceptions are deleted
3380 : : * pages, which contain no items.
3381 : : *
3382 : : * This is correct when pages are half-dead, since internal pages are
3383 : : * never half-dead, and leaf pages must have a high key when half-dead
3384 : : * (the rightmost page can never be deleted). It's also correct with
3385 : : * fully deleted pages: _bt_unlink_halfdead_page() doesn't change anything
3386 : : * about the target page other than setting the page as fully dead, and
3387 : : * setting its xact field. In particular, it doesn't change the sibling
3388 : : * links in the deletion target itself, since they're required when index
3389 : : * scans land on the deletion target, and then need to move right (or need
3390 : : * to move left, in the case of backward index scans).
3391 : : */
2881 teodor@sigaev.ru 3392 :CBC 22795 : maxoffset = PageGetMaxOffsetNumber(page);
3393 [ - + ]: 22795 : if (maxoffset > MaxIndexTuplesPerPage)
2881 teodor@sigaev.ru 3394 [ # # ]:UBC 0 : ereport(ERROR,
3395 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3396 : : errmsg("Number of items on block %u of index \"%s\" exceeds MaxIndexTuplesPerPage (%u)",
3397 : : blocknum, RelationGetRelationName(state->rel),
3398 : : MaxIndexTuplesPerPage)));
3399 : :
2131 akorotkov@postgresql 3400 [ + + + - :CBC 22795 : if (!P_ISLEAF(opaque) && !P_ISDELETED(opaque) && maxoffset < P_FIRSTDATAKEY(opaque))
+ + - + ]
2881 teodor@sigaev.ru 3401 [ # # ]:UBC 0 : ereport(ERROR,
3402 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3403 : : errmsg("internal block %u in index \"%s\" lacks high key and/or at least one downlink",
3404 : : blocknum, RelationGetRelationName(state->rel))));
3405 : :
2131 akorotkov@postgresql 3406 [ + + + - :CBC 22795 : if (P_ISLEAF(opaque) && !P_ISDELETED(opaque) && !P_RIGHTMOST(opaque) && maxoffset < P_HIKEY)
+ + - + ]
2881 teodor@sigaev.ru 3407 [ # # ]:UBC 0 : ereport(ERROR,
3408 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3409 : : errmsg("non-rightmost leaf block %u in index \"%s\" lacks high key item",
3410 : : blocknum, RelationGetRelationName(state->rel))));
3411 : :
3412 : : /*
3413 : : * In general, internal pages are never marked half-dead, except on
3414 : : * versions of Postgres prior to 9.4, where it can be valid transient
3415 : : * state. This state is nonetheless treated as corruption by VACUUM on
3416 : : * from version 9.4 on, so do the same here. See _bt_pagedel() for full
3417 : : * details.
3418 : : */
2881 teodor@sigaev.ru 3419 [ + + - + ]:CBC 22795 : if (!P_ISLEAF(opaque) && P_ISHALFDEAD(opaque))
2881 teodor@sigaev.ru 3420 [ # # ]:UBC 0 : ereport(ERROR,
3421 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3422 : : errmsg("internal page block %u in index \"%s\" is half-dead",
3423 : : blocknum, RelationGetRelationName(state->rel)),
3424 : : errhint("This can be caused by an interrupted VACUUM in version 9.3 or older, before upgrade. Please REINDEX it.")));
3425 : :
3426 : : /*
3427 : : * Check that internal pages have no garbage items, and that no page has
3428 : : * an invalid combination of deletion-related page level flags
3429 : : */
3293 andres@anarazel.de 3430 [ + + - + ]:CBC 22795 : if (!P_ISLEAF(opaque) && P_HAS_GARBAGE(opaque))
3293 andres@anarazel.de 3431 [ # # ]:UBC 0 : ereport(ERROR,
3432 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3433 : : errmsg_internal("internal page block %u in index \"%s\" has garbage items",
3434 : : blocknum, RelationGetRelationName(state->rel))));
3435 : :
1845 pg@bowt.ie 3436 [ - + - - ]:CBC 22795 : if (P_HAS_FULLXID(opaque) && !P_ISDELETED(opaque))
1845 pg@bowt.ie 3437 [ # # ]:UBC 0 : ereport(ERROR,
3438 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3439 : : errmsg_internal("full transaction id page flag appears in non-deleted block %u in index \"%s\"",
3440 : : blocknum, RelationGetRelationName(state->rel))));
3441 : :
1845 pg@bowt.ie 3442 [ - + - - ]:CBC 22795 : if (P_ISDELETED(opaque) && P_ISHALFDEAD(opaque))
1845 pg@bowt.ie 3443 [ # # ]:UBC 0 : ereport(ERROR,
3444 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3445 : : errmsg_internal("deleted page block %u in index \"%s\" is half-dead",
3446 : : blocknum, RelationGetRelationName(state->rel))));
3447 : :
3293 andres@anarazel.de 3448 :CBC 22795 : return page;
3449 : : }
3450 : :
3451 : : /*
3452 : : * _bt_mkscankey() wrapper that automatically prevents insertion scankey from
3453 : : * being considered greater than the pivot tuple that its values originated
3454 : : * from (or some other identical pivot tuple) in the common case where there
3455 : : * are truncated/minus infinity attributes. Without this extra step, there
3456 : : * are forms of corruption that amcheck could theoretically fail to report.
3457 : : *
3458 : : * For example, invariant_g_offset() might miss a cross-page invariant failure
3459 : : * on an internal level if the scankey built from the first item on the
3460 : : * target's right sibling page happened to be equal to (not greater than) the
3461 : : * last item on target page. The !backward tiebreaker in _bt_compare() might
3462 : : * otherwise cause amcheck to assume (rather than actually verify) that the
3463 : : * scankey is greater.
3464 : : */
3465 : : static inline BTScanInsert
1009 pg@bowt.ie 3466 : 2651469 : bt_mkscankey_pivotsearch(Relation rel, IndexTuple itup)
3467 : : {
3468 : : BTScanInsert skey;
3469 : :
3470 : 2651469 : skey = _bt_mkscankey(rel, itup);
828 3471 : 2651469 : skey->backward = true;
3472 : :
2552 3473 : 2651469 : return skey;
3474 : : }
3475 : :
3476 : : /*
3477 : : * PageGetItemId() wrapper that validates returned line pointer.
3478 : : *
3479 : : * Buffer page/page item access macros generally trust that line pointers are
3480 : : * not corrupt, which might cause problems for verification itself. For
3481 : : * example, there is no bounds checking in PageGetItem(). Passing it a
3482 : : * corrupt line pointer can cause it to return a tuple/pointer that is unsafe
3483 : : * to dereference.
3484 : : *
3485 : : * Validating line pointers before tuples avoids undefined behavior and
3486 : : * assertion failures with corrupt indexes, making the verification process
3487 : : * more robust and predictable.
3488 : : */
3489 : : static ItemId
2516 3490 : 6488606 : PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page,
3491 : : OffsetNumber offset)
3492 : : {
3493 : 6488606 : ItemId itemid = PageGetItemId(page, offset);
3494 : :
3495 [ - + ]: 6488606 : if (ItemIdGetOffset(itemid) + ItemIdGetLength(itemid) >
3496 : : BLCKSZ - MAXALIGN(sizeof(BTPageOpaqueData)))
2516 pg@bowt.ie 3497 [ # # ]:UBC 0 : ereport(ERROR,
3498 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3499 : : errmsg("line pointer points past end of tuple space in index \"%s\"",
3500 : : RelationGetRelationName(state->rel)),
3501 : : errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
3502 : : block, offset, ItemIdGetOffset(itemid),
3503 : : ItemIdGetLength(itemid),
3504 : : ItemIdGetFlags(itemid))));
3505 : :
3506 : : /*
3507 : : * Verify that line pointer isn't LP_REDIRECT or LP_UNUSED, since nbtree
3508 : : * never uses either. Verify that line pointer has storage, too, since
3509 : : * even LP_DEAD items should within nbtree.
3510 : : */
2516 pg@bowt.ie 3511 [ + - + - ]:CBC 6488606 : if (ItemIdIsRedirected(itemid) || !ItemIdIsUsed(itemid) ||
3512 [ - + ]: 6488606 : ItemIdGetLength(itemid) == 0)
2516 pg@bowt.ie 3513 [ # # ]:UBC 0 : ereport(ERROR,
3514 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3515 : : errmsg("invalid line pointer storage in index \"%s\"",
3516 : : RelationGetRelationName(state->rel)),
3517 : : errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
3518 : : block, offset, ItemIdGetOffset(itemid),
3519 : : ItemIdGetLength(itemid),
3520 : : ItemIdGetFlags(itemid))));
3521 : :
2516 pg@bowt.ie 3522 :CBC 6488606 : return itemid;
3523 : : }
3524 : :
3525 : : /*
3526 : : * BTreeTupleGetHeapTID() wrapper that enforces that a heap TID is present in
3527 : : * cases where that is mandatory (i.e. for non-pivot tuples)
3528 : : */
3529 : : static inline ItemPointer
2552 3530 : 3442 : BTreeTupleGetHeapTIDCareful(BtreeCheckState *state, IndexTuple itup,
3531 : : bool nonpivot)
3532 : : {
3533 : : ItemPointer htid;
3534 : :
3535 : : /*
3536 : : * Caller determines whether this is supposed to be a pivot or non-pivot
3537 : : * tuple using page type and item offset number. Verify that tuple
3538 : : * metadata agrees with this.
3539 : : */
2209 3540 [ - + ]: 3442 : Assert(state->heapkeyspace);
3541 [ - + - - ]: 3442 : if (BTreeTupleIsPivot(itup) && nonpivot)
2209 pg@bowt.ie 3542 [ # # ]:UBC 0 : ereport(ERROR,
3543 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3544 : : errmsg_internal("block %u or its right sibling block or child block in index \"%s\" has unexpected pivot tuple",
3545 : : state->targetblock,
3546 : : RelationGetRelationName(state->rel))));
3547 : :
2209 pg@bowt.ie 3548 [ + - - + ]:CBC 3442 : if (!BTreeTupleIsPivot(itup) && !nonpivot)
2209 pg@bowt.ie 3549 [ # # ]:UBC 0 : ereport(ERROR,
3550 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3551 : : errmsg_internal("block %u or its right sibling block or child block in index \"%s\" has unexpected non-pivot tuple",
3552 : : state->targetblock,
3553 : : RelationGetRelationName(state->rel))));
3554 : :
2209 pg@bowt.ie 3555 :CBC 3442 : htid = BTreeTupleGetHeapTID(itup);
3556 [ - + - - ]: 3442 : if (!ItemPointerIsValid(htid) && nonpivot)
2552 pg@bowt.ie 3557 [ # # ]:UBC 0 : ereport(ERROR,
3558 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3559 : : errmsg("block %u or its right sibling block or child block in index \"%s\" contains non-pivot tuple that lacks a heap TID",
3560 : : state->targetblock,
3561 : : RelationGetRelationName(state->rel))));
3562 : :
2209 pg@bowt.ie 3563 :CBC 3442 : return htid;
3564 : : }
3565 : :
3566 : : /*
3567 : : * Return the "pointed to" TID for itup, which is used to generate a
3568 : : * descriptive error message. itup must be a "data item" tuple (it wouldn't
3569 : : * make much sense to call here with a high key tuple, since there won't be a
3570 : : * valid downlink/block number to display).
3571 : : *
3572 : : * Returns either a heap TID (which will be the first heap TID in posting list
3573 : : * if itup is posting list tuple), or a TID that contains downlink block
3574 : : * number, plus some encoded metadata (e.g., the number of attributes present
3575 : : * in itup).
3576 : : */
3577 : : static inline ItemPointer
3578 : 6 : BTreeTupleGetPointsToTID(IndexTuple itup)
3579 : : {
3580 : : /*
3581 : : * Rely on the assumption that !heapkeyspace internal page data items will
3582 : : * correctly return TID with downlink here -- BTreeTupleGetHeapTID() won't
3583 : : * recognize it as a pivot tuple, but everything still works out because
3584 : : * the t_tid field is still returned
3585 : : */
3586 [ + + ]: 6 : if (!BTreeTupleIsPivot(itup))
3587 : 4 : return BTreeTupleGetHeapTID(itup);
3588 : :
3589 : : /* Pivot tuple returns TID with downlink block (heapkeyspace variant) */
3590 : 2 : return &itup->t_tid;
3591 : : }
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